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21 APRIL 29, 2014 APRIL MENDOZA,ARGENTINA THE IMPACT ON WINE QUALITY THE IMPACT NEW OUTLOOK IN VITICULTURE AND IN VITICULTURE NEW OUTLOOK

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E WIN T IN TION A FERMEN CTIC L A L O MA

NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY APRIL 29, 2014 APRIL

MENDOZA,ARGENTINA 21 MENDOZA, ARGENTINA, APRIL 29, 2014

NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

PROCEEDINGS OF THE XXVes ENTRETIENS SCIENTIFIQUES LALLEMAND

FOREWORD

t the XXVes Entretiens Scientifiques Lallemand, Aromas y Sabores DICTUC in Chile, presented work fo- viticulture experts updated attendees on cur- cused on the other end of the wine spectrum – key aroma Arent knowledge in viticulture science. The ses- compounds and how they affect consumer preferences. sion opened with Alain Deloire from the National Wine In but one example, he discussed how thiols, which are and Grape Industry Centre of Charles Sturt University in influenced by viticultural practices and other factors, are Wagga Wagga, Australia, who discussed the complexity rated by consumers and orient their choices. of fruit composition, including its impact on wine style Fernando Zamora from Universitat Rovira I Virgili in and consumer preferences. He also discussed vine physi- Spain began his presentation by describing the changes ology and the genetic factors influencing grape quality. to anthocyanin and tannin concentrations in red grapes His introduction to the topic of viticulture gave a great throughout ripening. He then explained the various meth- overview of this very complex science. Jorge Perez Peña, ods that exist for determining phenolic maturity (e.g., from INTA EEA Mendoza, gave an excellent talk on Ar- Glories, ITV, AWRI, Cromoenos, etc.), stating the pros and gentinean viticulture and the many challenges faced by cons of each. He also presented various experimental re- vine growers – most importantly, climate change – and sults from his research group to illustrate the influence of how to adapt to this reality. Heat waves in particular are grape phenolic maturity on the composition and quality affecting vineyards, and different strategies are being stud- of red wines. ied at his research station. Andrew G. Reynolds from the Cool Climate Oenology and Viticulture Institute at Brock To close the day, José Ramón Lissarrague of Universidad University in Canada presented on the different aroma Politécnica de Madrid presented the results of a study compounds and precursors in grapes and how they are done by his research group on the impact of yeast de- affected by viticultural practices. A summary of the impact rivatives on the phenolic maturity and aroma profiles of of cluster exposure, vineyard irrigation, nitrogen status, wine when applied in the vineyard. His studies show fruit exposure, grape maturity, and how these affect the that, while the topic is completely new and research is levels of volatile thiols, terpenes, methoxypyrazines, nor- underway, there is a definite trend toward better phenolic isoprenoids and volatile phenols was presented. maturity, more aromatic complexity and heightened sensory preference upon tasting. A bright future is in store for Hernán Ojeda, also from Argentina but now a researcher natural vineyard products. at INRA Unité expérimentale de Pech Rouge, in France, discussed the main factors affecting grape and wine char- Learning about viticulture and understanding the con- acteristics – from biological and natural factors to crop- cerns and limitations winegrowers face in producing related issues – and how different solutions need to be quality grapes was the aim of the XXVes Entretiens Scien- researched in order to optimize grape quality in light of tifiques Lallemand. these impacts. Gerard Casaubon, the director of Centro de Investigación e Innovación Concha y Toro and Centro de

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CONTENTS

NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY EVIDENCE OF COGNITIVE IMPACT OF ODOUR SEQUENTIAL HARVEST AND WINE STYLE: RECOGNITION TRAINING: INTERMODALITY WHAT DOES THE FRUIT PHYSIOLOGICAL BY LEARNING WINE AROMAS...... 53 INDICATOR HAVE TO OFFER?...... 7 Gerard CASAUBON, David CARRÉ, Alain DELOIRE María Ines ESPINOZA, José CHIANALE, Eduardo AGOSÍN and Carlos CORNEJO IMPACT OF VINEYARD MANAGEMENT ON GRAPE MATURITY: FOCUS ON TERPENES, PHENOLICS, PHENOLIC MATURITY: CONCEPT, AND OTHER SECONDARY METABOLITES...... 13 METHODOLOGY AND OENOLOGICAL Andrew G. REYNOLDS and Gabriel BALINT IMPLICATIONS...... 57 Fernando ZAMORA PRECISION IRRIGATION OF GRAPEVINES: METHODS, TOOLS AND STRATEGIES TO MAXIMIZE IMPACT ON AGRONOMIC PARAMETERS IN THE QUALITY AND YIELD OF THE HARVEST, AND VINES AND WINE QUALITY OF FOLIAR ENSURE WATER SAVINGS...... 43 TREATMENTS WITH SPECIFIC FRACTIONS OF Hernán OJEDA, and Nicolas SAURIN YEAST DERIVATIVES...... 65 Javier TÉLLEZ, Elisa GARCÍA, Emilio PEIRO, Vanesa GONZÁLEZ, José Ramón LISSARRAGUE

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SEQUENTIAL HARVEST AND WINE STYLE: WHAT DOES THE FRUIT PHYSIOLOGICAL INDICATOR HAVE TO OFFER?

Alain DELOIRE

National Wine and Grape Industry Centre, Charles Sturt University, Locked Bag 588, Wagga Wagga NSW, 2678, Australia

Abstract cultivars, and provide some information on berry development. The optimal maturity of grapes depends on multi-faceted criteria. Water status, light (quality and quantity) and temperature (day and night, heat waves) may hasten, delay or Introduction enhance ripening. A berry will regulate genes responsible The grapevine is an important perennial crop in the world for the biosynthesis of specific compounds (phenolics, (7.6 million hectares under production), and complex aromatic precursors, hormones, organic acids, amino ac- but poorly understood processes occur in the grapevine ids, etc.), while other compounds are provided by roots during berry growth and development. In particular, the and/or leaves (water, minerals, sugar, nitrogen, etc.). For determination of final fruit composition from flowering some compounds, such as tannins, one has to consider to veraison and from veraison to ripening requires further the evolution of the structure and the binding of these investigation. It is known that berry development follows molecules over the fruit growth and ripening period. The a double-sigmoid growth pattern consisting of two dis- volume of the fruit could determine the concentration or tinct growth phases separated by a lag phase (figure 1) dilution of these compounds. Optimal grape ripeness is (Coombe 1992). Several compounds accumulate during defined according to the desired wine style, which in turn the first growth period, such as tannins, amino acids and is dictated by market demand or by the objective of pro- some aroma compounds, including methoxypyrazines ducing a wine that expresses the typicity of the location. in the Sauvignon Blanc, Cabernet Sauvignon and Mer- Professionals in the wine sector are therefore obliged to lot cultivars (figure 2) (Kennedy et al. 2001, Ollat et al. accurately characterize the grapes in order to make an 2002, and Šuklje et al. 2012). Berry growth and organic informed decision about the optimum harvest date, and acid accumulation will cease during the lag phase. Ac- to adapt the winemaking process to obtain the targeted cording to Terrier et al. (2005) and Pilati et al. (2007), the wine style. most significant changes in gene expression occur during The evolution of sugar accumulation per berry in red the 24-hour transition phase between the lag phase and grape berry cultivars gives an indication of the ripening veraison (i.e., individual berry softening and the onset of process from a new perspective. This indicator aims to ripening). Dal Santo et al. (2013) showed the same effect help winegrowers and winemakers predict the grape har- on Corvina grapes via a study on the plasticity of the berry vest dates that will deliver optimum results according to transcriptome using a network of commercial vineyards to the wine style. Depending on the variety, the harvest can assess the effect of the site (soil x climate) and the vintage. be planned 10 to 40 days before it is due to start, allowing The data of this study suggested that, “veraison is a critical producers to plan ahead for harvest and wine production. period during which the seasonal climate has its great- This article will present the method developed for the red est effect whereas the microenvironment and agronomic – 7 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY practices had only marginal impact.” The impact of ag- of analytical equipment and the ability to interpret the ronomic practices and environmental conditions seemed analytical data. to have an important effect during ripening. Šuklje et al. Geographical origin is important for products that lay (2012 and 2014) demonstrated that canopy manipulation claim to a terroir-linked typicality. Measuring the terroir had a considerable effect on fruit and wine composition, effect on an agri-food product remains difficult for both which influenced the final wine sensory profile. Leaf re- trained experts and consumers, for whom the apprecia- moval was practised on Sauvignon Blanc at an early stage tion of the product or lack thereof remains the principal of berry growth (berry pea size), and methoxypyrazine criterion in their evaluation. This does not exclude the and thiol levels were shown to be influenced. ability to recognize the product’s properties, but it should A recent study from Rienth et al. (2014) showed changes be remembered that the perceived taste and aromas will in berry gene expression during night development that be transformed by the individual’s experience into a differed from daytime development. This emphasizes the unique overall sensory impression (Deloire et al. 2008). importance of measuring both day and night temperatures The quality of the grapes is a determining factor in the over the entire growth period when the effect of the cli- quality of the finished wine. But how is grape quality itself mate on fruit metabolism and vine physiology is being determined? What are the relevant parameters of the berry investigated. that enable the dynamics of ripening to be monitored?

All the above-mentioned studies have demonstrated the One of the most important and difficult parts of a viticul- importance of the environment for the final grape compo- turist’s and winemaker’s job is to predict the wine style sition at harvest. from the berries and the oenological process. The classical indicators like Brix, malic and tartaric acids, titratable The ideal timing of the harvest is currently being decided acidity, tannins, anthocyanins, etc. are relevant indicators by viticulturists and winemakers using the following cri- of grape ripeness. They are strongly related to the percep- teria: tion of the taste of the wine (mouthfeel), but they give no • According to a single criterion, the measurement of to- indication on wine aromatic profile. Therefore, it would tal soluble solids expressed as Brix. This requires sim- be also highly useful to predict or predetermine the future ple, routine analysis and is the most commonly used wine style in terms of aromatic profile using fruit-related indicator in the wine industry today. physiological indicators.

• According to berry tasting. This can be relevant but Berry ripening, wine flavours and the elaboration of aro- highly subjective as the decision is influenced by the matic low-alcohol wines are, today, among the priorities taster’s personal experience and training. of the worldwide wine industry, mainly in the context of climate change (i.e., the increase of temperature and un- • Using a series of indicators and appropriate analysis predictable heat wave events) and scarcity of water. methods (anthocyanins, titrable acidity, tannins, etc.). This implies that the necessary equipment is available Proposed method for red cultivars at the estate or at an appropriate laboratory nearby. Knowledge in interpreting analytical results to make the This method is based on the indirect relations established appropriate decision is therefore required. The cost per between the use of a fruit physiological indicator (i.e., analysis and per hectare has to be considered. sugar accumulation per berry) and the possible wine styles determined by wine sensory analyses or tasting sessions. • To harvest using new decision-making tools and taking The method is based on sequential harvests to understand into consideration new scientific results. This implies the relation between the harvest time and the wine com- the ability to access the information, understand and position and profile (Bindon et al. 2013, Deloire, 2011, assimilate it, then implement it successfully (extension 2013, and Wang et al. 2003) (figure 3). Sequential har- and adoption process). In addition, the ability to afford vests using the fruit sugar accumulation profile helped de- this new technology, which may be expensive, has to termine four stages during ripening (figure 4). be considered. As shown in figure 4 for Syrah and Cabernet Sauvignon, This list is not complete. It is also important that skills and stage 1 (fresh fruit) always occurs from 12 to 20 days on- information are transferred to the individuals who are us- wards after the sugar per berry has reached a plateau (the ing these methods to determine the harvesting date. Such termination of berry sugar loading or the slowdown of skills include an appropriate sampling procedure, the use berry sugar accumulation). Stage 3 (mature fruit) always – 8 – Sequential Harvest and Wine Style: What Does the Fruit Physiological Indicator Have to Offer? occurs from 24 to 40 days onwards after the sugar per only the Brix value cannot really help predict the harvest berry has reached a plateau (figure 4). Between the fresh date and wine style. (See figure 1 on this page, and figures and mature fruit stages, stage 2 is called neutral (i.e., a 2, 3 and 4 on the next pages) deficiency of fruitiness in the related wine, which can en- No doubt climate change will influence berry ripening hance the perception of “spicy” and “peppery” charac- and this may have repercussions for the time of harvest teristics in Shiraz wine), or premature (in some situations, and the style of wine produced. The concept of grape there is an overlap between fresh and mature fruit stages) quality at harvest should be considered in terms of the and may vary according to the site (climate and soil) and cultural practices. In most situations, it is recommended required fruit and wine composition and the winemaking to avoid stage 2 when it is considered neutral as the relat- process, resulting in wine with particular sensory prop- ed wines will show a deficiency of fruitiness and could be erties. Numerous important studies have recently looked judged as one-dimensional. Stage 2 can be determined/ at the relationship between grape and wine composition predicted using the sugar-loading method. Interestingly, and the wine’s aromatic profile (Ristic et al. 2007, Kalua there is a market for “spicy” and “peppery” Shiraz wines and Boss 2009 and 2010, Sweetman et al. 2012, and Ca- produced in Australia, for example in the Grampians re- pone et al. 2012), whereas other studies have emphasized gion of Victoria (Scarlet et al. 2014). It is suggested that some wine markers potentially linked to wine aromatic stage 2 of the berry’s aromatic evolution could be target- maturity (Pineau et al. 2009, Lytra et al. 2012, Dubour- ed for this style of wine, meaning that the harvest date dieu et al. 2012, and Pons et al. 2013). Despite all these chosen according to the relevant physiological indicator important new insights, the topic is so complex that the could help achieve these production goals. relationship between the grape and wine composition, There is no direct relationship between fruit Brix or titra- and the wine’s sensory profile associated with the differ- ble acidity levels and the berry aromatic profile evolution, ent stages of fruit maturity remain poorly understood. The meaning that fresh, neutral and mature stages could be role of the fermentation processes should definitely be reached at approximately the same sugar concentration. considered as strongly impacting the wine composition In that regard, the model showed that to harvest using and sensory profiles.

Green growth Lag phase Maturation stage II II I Berry volume

Days 0 20 40 60 80 100 120 140 Days after ﬂowering Flowering Veraison Maturation Maturity over ripeness

Figure 1. Curve of berry growth from flowering to harvest showing the three stages (green growth stage, lag phase and maturation) – 9 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

Green growth Lag phase Maturation stage II II I

Tannins Organic acids Pyrazines Amino acids Polyamines Anthocyanins Carotenoids Thiol precursors Tannin structure evolution?

Berry volume Sugar accumulation Amino acids

Days 0 20 40 60 80 100 120 140 Days after ﬂowering Flowering Veraison Maturation Maturity over ripeness

Figure 2. Examples of compound biosynthesis during fruit development

Ripening levels and sugar accumulation per berry Fresh fruit, Fresh Neutral Ripe Jammy grassy skin fruit or pre-ripe fruit fruit Pre-fresh

Grassy

Possible evolution of the ﬂavours

Time for berry softening

Figure 3. A proposed sequence of ripening for red cultivars and possible relations between grape sequential harvest times and wine aromatic profiles – 10 – Sequential Harvest and Wine Style: What Does the Fruit Physiological Indicator Have to Offer?

Accumulation of sugar per berry

Proposed evolution of ripening

Window to harvest for overripe fruit Window to harvest for mature fruit Window to harvest for fresh fruit

0 12 17 24 30 35 Days Beginning of veraison (berry softening) Day 0 = when sugar per berry reaches a plateau, preferably at 20° to 22° Brix

Figure 4. Example of Syrah ripening evolution, using sequential harvest. A vine or a vineyard is said to be “in balance” when sugar accumulation stops or slows down around 20° to 22° Brix, 20 to 30 days after berry softening. It is site- and cultural practices-related

The method presented in this article is not exclusive and of 1,8-Cineole in Australian red wine. Journal of Agricul- needs further investigation. It is important to understand tural and Food Chemistry. 60:2281-2287. the relation between fruit and wine composition and wine Coombe, B. G. 1992. Research on development and style using sequential harvest dates. ripening of the grape berry. Am. J Enol Vitic. 43:101-110.

Acknowledgments Dal Santo, S., G. V. Tornielli, S. Zenoni, M. Fasoli, L. Fai- na, A. Anesi, F. Guzzo, M. Delledonne, and M. Pezzotti. We thank Distell, Stellenbosch University (DVO) and 2013. The plasticity of the grapevine berry transcriptome. Winetech for funding and helping develop the methods Genome Biology, for South Africa, and GWRDC (Australia) for funding a project on fruit and wine composition and wine style and Deloire, A. 2011. The concept of berry sugar loading. predicting the harvest date. We thank Vivelys (France) for Wineland. 257:93-95. providing some of its data and expert knowledge. Deloire, A. 2013. Berry ripening and wine aroma. Practi- cal Winery & Vineyard. April, 1-2. References Deloire, A., P. Prevost, and M. T. Kelly. 2008. Unravelling Bindon, K., C. Varela, J. Kennedy, H. Holt, and M. the terroir mystique – An agro-socio-economic perspec- Herderich. 2013. Relationships between harvest time tive. Cab Reviews: Perspectives in Agriculture, Veterinary and wine composition in Vitis vinifera L. Cv. Cabernet Science, Nutrition and Natural Resources. 3(32). Sauvignon 1. Grape and wine chemistry. Food Chemis- Dubourdieu, D., A. Pons, and V. Lavigne. 2012. Le vieil- try. 138:1696-1705. lissement prématuré de l’arôme des vins rouges : identifi- Capone, D. L., D. W. Jeffery, and M. A. Sefton. 2012. cation de nouveaux marqueurs. Proceedings of Colloque Vineyard and fermentation studies to elucidate the origin arômes du vin, Projet VINAROMAS, November 20, 2012, – 11 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

Toulouse, France; November 22, 2012 Zarogoza, Spain tannin and sensory properties. Aust. J. Grape Wine Res. (http://www.vignevin-sudouest.com/publications/itv- 13:53-65. colloque/documents/actes-complets-francais-espagnol. Scarlett, N. J., R. G. V. Bramley, and T. E. Siebert. 2014. pdf) 27-30. Within-vineyard variation in the ‘pepper’ compound Kalua, C. M., and P. K. Boss. 2009. Evolution of volatile rotundone is spatially structured and related to variation compounds during the development of Cabernet Sauvi- in the land underlying the vineyard. Aust. J. Grape Wine gnon grapes (Vitis vinifera L.). Journal of Agricultural and Res. 20:214-222. Food Chemistry. 57:3818-3830. Šuklje, K., G. Antalick, Z. Coetzee, L. M. Schmidtke, Kalua, C. M., and P. K. Boss. 2010. Comparison of major H. Baša Cˇesnik, J. Brand, W. Du Toit, K. Lisjak, and A. volatile compounds from Riesling and Cabernet Sau- Deloire. 2014. Effects of leaf removal and ultraviolet vignon grapes (Vitis vinifera L.) from fruitset to harvest. radiation in the vineyard on the composition and sensory Aust. J. Grape Wine Res. 16:337-348. perception of Sauvignon Blanc (Vitis vinifera L.) wine. Aust. J. Grape Wine Res. 20:223-233. Kennedy, J. A., Y. Hayasaka, S. Vidal, E. J. Waters, and G. P. Jones. 2001. Composition of grape skin proanthocy- Šuklje, K., K. Lisjak, H. Baša Cˇesnik, L. Janeš, W. Du Toit, anidins at different stages of berry development. Aust. J. Z. Coetzee, A. Vanzo, and A. Deloire. 2012. Classifica- Grape Wine Res. 49:5348-5355. tion of grape berries according to diameter and total soluble solids to study the effect of light and temperature Lytra, G., S. Tempere, G. de Revel, and J. C. Barbe. on methoxypyrazine, glutathione, and hydroxycinna- 2012. Impact of perceptive interactions on red wines mate evolution during ripening of Sauvignon blanc (Vitis fruity aroma. Journal of Agricultural and Food Chemistry. vinifera L.). Journal of Agricultural and Food Chemistry. 60:12260-12269. 60:9454-9461.

Ollat, N., P. Diakou-Verdin P, J. P. Carde, F. Barrieu, J. P. Sweetman, C., D. C. J. Wong, C. M. Ford, and D. P. Gaudillere, and A. Moing. 2002. Grape berry develop- Drew. 2012. Transcriptome analysis at four developmen- ment: a review. Journal International des Sciences de la tal stages of grape berry (Vitis vinifera cv. Shiraz) provides Vigne et du Vin. 36(3):109-131. insights into regulated and coordinated gene expression. BMC Genomics. 13:691. Pilati, S., M. Perazzolli, A. Malossini, A. Cestaro, L. Dematté, P. Fontana, A. Dal Ri, R. Viola, R. Velasco, and Terrier, N., D. Glissant, J. Grimplet, F. Barrieu, P. Abbal, C. Moser. 2007. Genome-wide transcriptional analysis of C. Couture, A. Ageorges, R. Atanassova, C. Leon, J. P. grapevine berry ripening reveals a set of genes similarly Renaudon, F. Dédaldéchamp, C. Romieu, S. Delrot, and modulated during three seasons and the occurrence of S. Hamdi. 2005. Isogene specific oligo arrays reveal mul- an oxidative burst at veraison. BMC Genomics. 8:428. tifaceted changes in gene expression during grape berry (Vitis vinifera L.) development. Planta. 222(5):832-847. Pineau, B., J. C. Barbe, C. Van Leeuwen, and D. Dubour- dieu. 2009. Examples of perceptive interactions involved Wang, Z. P., A. Deloire, A. Carbonneau, B. Federspiel, in specific “red-and-black-berry” aromas in red wines. and F. Lopez. 2003. An in vivo experimental system to Journal of Agricultural and Food Chemistry. 57:3702- study sugar phloem unloading in ripening grape berries 3708. during water deficiency stress. Annals of Botany. 92:523- 528. Pons, A., V. Lavigne, P. Darriet, and D. Dubourdieu. 2013. Role of 3-methyl-2,4-nonanedione in the flavor of aged red wines. Journal of Agricultural and Food Chemis- try. 61:7373-7380.

Rienth, M., L. Torregrosa, M. T. Kelly, N. Luchaire, A. Pel- legrino, J. Grimplet, and C. Romieu. 2014. Is transcrip- tomic regulation of berry development more important at night than during the day? PLoS ONE 9(2):1-9.

Ristic, R., M. O. Downey, P. G. Iland, K. Bindon, I. L. Francis, M. Herderich, and S. P. Robinson. 2007. Exclu- sion of sunlight from Shiraz grapes alters wine colour, – 12 – IMPACT OF VINEYARD MANAGEMENT ON GRAPE MATURITY: FOCUS ON TERPENES, PHENOLICS AND OTHER SECONDARY METABOLITES

Andrew G. REYNOLDS and Gabriel BALINT

Brock University, St. Catharines, Ontario, Canada

1. Introduction less and Koblet et al. (1977) with Pinot Noir. Both studies found that fruit exposure increased soluble solids (%SS), All plants, grapes included, possess a multitude of primary biochemical pathways that are essential for their growth reduced titratable acidity (TA) and increased pH. Reyn- and survival. These include well-known processes such olds et al. (1986) found a sizable (1.2ºBrix) difference be- as respiration, photosynthesis, photorespiration, nitrogen tween shaded and exposed Seyval Blanc clusters on vines metabolism, sulphur metabolism and many others. How- of identical training and crop level. They also noted as ever, there are numerous other pathways that are utilized much as 12ºC difference in berry temperature between by plants to create products that are collectively known western-exposed berries and shaded berries, which di- as secondary metabolites. These include monoterpenes, minished the diurnal temperature flux of the exposed ber- phenolics and anthocyanins, norisoprenoids, aliphatic hy- ries. Greater malate degradation also occurred in exposed drocarbons (esters, aldehydes, alcohols, ketones), alkaloids clusters. Similar studies on the effect of cluster shading and perhaps others. None of these compounds are essen- found higher %SS in clusters of Cabernet Sauvignon from tial for plant survival; however, they are well known to en- sun-exposed regions of the canopy (Crippen and Morrison hance the plant’s ability to adapt to its environment—many 1986a, b). The shaded berries were larger and had higher of these compounds provide the basis for insect or disease water content than the exposed berries, effectively lower- resistance, prevention of herbivory, attraction of pollinizing ing %SS. Pre-harvest, anthocyanins were higher on both and/or beneficial insects and a plethora of other functions. a berry weight and per berry basis, but by harvest there In wines, many of these secondary metabolites provide the were no differences (Crippen and Morrison 1986a, b). basis for quality—monoterpenes, norisoprenoids and some Bergqvist et al. (2001) assessed the effects of sunlight hydrocarbons are odour-active substances, many phenolics exposure on berry growth and composition of two red are responsible for bitterness, astringency and wine mouthfeel, and anthocyanins are essential for colour. wine grape cultivars (Cabernet Sauvignon and Grenache) grown in the central San Joaquin Valley of California. Sun- light exposures ranged from mid-day photosynthetically 2. General Impacts of Viticultural Practices on active radiation (PAR) < 10 μmol·m-2·sec-1 (shaded) to Grapes and Wines > 600 μmol·m-2·sec-1 (fully exposed) from berry set to 2.1 Effects of fruit exposure harvest. Experimental clusters were evenly distributed be- The effects of cluster shading on fruit composition can be tween the north (afternoon shaded) and south (afternoon quite substantial. Enhancement of cluster exposure will exposed) sides of the canopy. Fruit response to sunlight increase berry temperature and will lead to upregula- varied based on cluster location within the canopy, and tion of crucial enzyme systems. Two seminal studies are these results were at least partially due to large differences those of Kliewer and Lider (1968) with Thompson Seed- in berry temperature. At the same exposure level or PAR, – 13 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY mid-day berry temperature was generally 3 to 4°C greater formed, mevalonic acid may undergo two successive phos- for clusters on the south side of the canopy compared phorylations to form mevalonate-5-pyrophosphate, which to clusters on the north. %SS initially increased with is oxidized to form isopentyl pyrophosphate (IPP). IPP may greater sunlight exposure, then declined when mid-day then undergo isomerization to form dimethylallyl pyro- PAR exceeded 31 to 50 and 51 to 100 μmol·m-2·sec-1 phosphate (DMAPP) such that an equilibrium between the respectively for clusters on the north and south sides of two is set up. Additionally, a second pathway known as the the canopy. Juice TA generally declined as sunlight expo- methylerythritol phosphate pathway can create DMAPP sure increased, with Cabernet Sauvignon clusters on the from glyceraldehyde-3-phosphate and pyruvate. Plants north side of the canopy maintaining greater acidity at the appear to maintain an active pool of DMAPP. Subsequent same exposure level as clusters on the south. Juice pH condensation of the two compounds with prenyltransfer- declined as exposure increased on the north side of the ase produces the universal terpene precursor, geranyl py- canopy, while sunlight had little effect on pH for clusters rophosphate (GPP), which can be converted easily to most on the south. These results suggested that the effects of of the other major monoterpenes. These compounds can light on fruit composition are heavily dependent upon the occur free, as pyrophosphates, or as glycosides; the latter extent to which berry temperature is elevated because of were first shown in Muscat of Alexandria by Cordonnier increased sunlight exposure. and Bayonove (1974), who found that linalool glycosides were cleaved by -glycosidases into the sugar and the 2.2 Effects of growing season canopy management much more organoleptically-active free terpene. Vertically shoot-positioned canopies are typically hedged at the top and sides of the canopies to eliminate overhang- Monoterpene aroma compounds are created in the ber- ing shoots, reduce canopy width and generally reduce ries. This is supported by the fact that when clusters of shade in dense canopies. Normally this is done about two the intensely flavoured Muscat Albardiens were grafted weeks after fruit set, but can be repeated one or more after fruit set to neutral-flavoured Olivette Blanche, the times during the growing season. Basal leaf removal is characteristic Muscat flavour still developed in the grafted generally done one week or more after hedging by remov- cluster; the berries, immediately after fruit set, acquire ing the lower two to four leaves at the base of the shoot to the enzymatic capacity inherent in the genotype for the expose the clusters. This can be done on both sides of the conversion of translocated precursors to specific aroma canopy, particularly in the case of red wine cultivars and compounds (Winkler et al. 1974). Similar results were ob- during wet growing seasons; typically it is done on the tained in other more recent cluster-transfer trials involving least sunny side (east or north side in the Northern Hemi- Shiraz and Muscat of Alexandria (Gholami et al. 1995). sphere) to avoid the possibility of sunburning the fruit. V. vinifera cultivars possess an almost continuous grada- Research into the potential effects of hedging and leaf re- tion of aroma characters from the very neutral (Grenache, moval on potential wine quality has been quite recent. Sylvaner) through pronounced aromatic types (Chardon- Many of these studies measured standard fruit composition nay, Riesling) to the very intense Muscat character (Mus- variables and not aroma compounds. A New Zealand study cat of Alexandria, Gewürztraminer). The latter aroma unequivocally found that basal leaf removal (either 50% or character, owing to its great desirability, has been investi- 100% of leaves in fruit zone) increased both total phenol gated very extensively both from the aspect of its flavour and anthocyanin concentrations in Cabernet Sauvignon, chemistry and its inheritance. with the greatest increase (≈50% over control) occurring when the treatment was done five weeks after flowering Webb and Kepner (1957) used gas chromatography-mass (Smith et al., 1988). Mazza et al. (1999) also found that spectrometry (GC-MS) and reported numerous com- leaf removal resulted in higher phenolic concentration and pounds in Muscat of Alexandria but no monoterpenes, colour density over the control. Numerous studies on basal which are the compounds that give this cultivar its unique leaf removal have been performed on aromatic white wine characteristics. Although they failed to detect terpenes, cultivars, e.g., basal leaf removal on Chardonnay vines in they did identify five alcohols, three aldehydes and eight New York increased %SS and lowered TA (Wolf et al. 1986). esters, as well as several unidentified ethyl esters and ac- etals. Early investigations in Europe (Austerweil, 1946; Cordonnier, 1955, 1956) noted that high concentrations 3. Monoterpenes of terpenes, particularly linalool, geraniol, limonene, and 3.1 Biogenesis of monoterpenes -terpineol, were associated with Muscat-flavoured cul- Mevalonic acid is the well-known precursor of all ter- tivars. Eventually, other studies found many significant penoid compounds in the mevalonate pathway. Once compounds. Bayonove and Cordonnier (1971a) further – 14 – Impact of Vineyard Management on Grape Maturity

supported their previous work that terpenes were respon- vars such as Müller-Thurgau. In a comprehensive study of sible for the aromas in Muscat and aromatic cultivars by the Muscat character, Ribéreau-Gayon et al. (1975) finally quantifying linalool and other terpenes in several of these collated much of the prior work on the subject into some cultivars. Volatile compounds could now be targeted spe- plausible conclusions. The threshold values of many of cifically and therefore more sense could be made out of the terpenes, especially linalool and geraniol, were found all the “noise” of chromatograms. to be extremely low (100 and 132 µg/L, respectively), and so it was felt that the contribution of these terpenes to the GC-MS nuanced the study of the volatile components of aroma was very significant. They also cited the phenom- the Muscat aroma and that of aromatic grape cultivars. enon of synergism between terpenes in musts and wines, Early work utilizing classical methods alluded to the such that a greater intensity of aroma was produced. strong possibility that terpenes were major contributors to the aroma. Stevens et al. (1966) identified 19 hydro- Studies on the volatile composition of other aromatic V. vi- carbons, 15 alcohols, 13 esters, 4 aldehydes, 2 ketones nifera cultivars have led to some conclusions. Drawert and and 6 miscellaneous compounds. Linalool, geraniol and Rapp (1966) and van Wyck et al. (1967) both conducted hexanol were found to be the major components. Webb exhaustive studies into the constituents of Riesling aroma. et al. (1966), in examining the low-boiling volatile frac- The latter group concluded that the characteristic Riesling tions of eight Muscat cultivars, found that linalool con- aroma could be attributed to specific concentrations of lin- centration varied greatly between the cultivars, from alool, 2-phenylethyl alcohol, ethyl acetate and 2-methyl- very high to trace amounts. Bayonove and Cordonnier 1-butanol. Schreier et al. (1976) identified 81 previously (1970b, 1971a) obtained similar results, but still felt the unreported compounds in Riesling, as well as six other pop- terpene fraction to be the major contributor to the Mus- ular German cultivars, but they failed to specify from which cat aroma, despite its oftentimes low concentration. These cultivars the various constituents were isolated. Kormokova same authors (1971b), however, also found large vol- and Rodopoulo (1974), in their study of the essential oils of umes of linalool in non-Muscat-flavoured selections, and sparkling wine cultivars grown in the USSR, considered ge- so concluded that linalool was “important but not spe- raniol to be the major component of the aroma of Rkatsiteli, cific” insofar as its role as an aroma constituent in Mus- a popular Russian cultivar of distinct aromatic character. cats was concerned. Terrier et al. (1972a, b) substantiated Sixty-nine other constituents were also identified. this observation by the identification of several terpenes in aromatic cultivars such as Riesling; no terpenes were 3.2. Effects of fruit exposure on monoterpenes detected in neutral-flavoured cultivars such as Grenache. The distillation method of Dimitriadis and Williams Rodopoulo et al. (1974) conducted an exhaustive study (1984) permitted the assessment of viticultural practices into the composition of the essential oils of Muscat Fron- on concentrations of monoterpenes in grape berries with tignan, Saperavi and two other Muscat-flavoured cultivars rapid throughput. One of the first of these was a study grown in Armenia and the Crimea. Esters and terpenes in British Columbia whereby potentially volatile terpene were the principal components of the essence. Schreier (PVT) concentrations in Gewürztraminer berries were et al. (1976) identified another monoterpene alcohol, hot- found to be highest in fully exposed clusters throughout rienol (3,7-dimethyl-l,5,7-octatrien-3-ol), which they be- the course of fruit maturation, but peaked at about 20 lieved to have significance in the Muscat aroma of culti- days after veraison (Reynolds and Wardle, 1989b)(Fig. 1).

1.60 2.75 A-Free volatile terpenes B-Potentially volatile 1.50 2.50 1.40 terpenes 1.30 2.25 1.20 2.00 1.10 1.00 1.75 0.90 1.50 0.80 1.25 0.70 NS NS NS NS * NS * ** *** ** * ***

Free volatile terpenes (mg/L) 0.60 1.00 08/26/86 08/31/86 09/05/86 09/10/86 09/15/86 09/20/86 09/25/86 09/30/86 08/26/86 08/31/86 09/05/86 09/10/86 09/15/86 09/20/86 09/25/86 09/30/86 Date (1986) Date (1986)

Exposed Partially shaded Shaded Potentially volatile terpenes (mg/L) Exposed Partially shaded Shaded

Figure 1. Effects of cluster exposure on monoterpene composition of Gewürztraminer, Kaleden, British Columbia, 1986: A: Free volatile terpenes (mg/L); B: Potentially volatile terpenes (mg/L). *,**,***, ns: Significant at p< 0.05, 0.01, 0.001, or not significant, respectively. Redrawn from Reynolds and Wardle (1989b). – 15 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

Partially exposed clusters (those shaded by one layer of aroma and flavour in both the hedged and leaf removal leaves) contained a lower concentration of PVT than ex- wines than in the control. posed clusters, but much more than shaded clusters. Free FVT and PVT in the berries of Pearl of Csaba, Bacchus, volatile terpenes (FVT) were not as responsive to fruit ex- Schönburger and Siegerrebe were responsive to basal leaf posure as PVT, but followed the same trends. By the final removal during the veraison-to-harvest period at several sampling date, %SS, TA and pH were similar among the sites in British Columbia (Reynolds et al. 1995a). Musts three exposure treatments, but exposure-related differ- displayed greater treatment differences, and basal leaf ences in PVT remained until after commercial maturity. removal musts usually contained higher FVT and PVT. Conclusions were that fruit exposure enhances monoter- %SS and TA were largely unresponsive to basal leaf re- pene concentrations in grape berries and that FVT and moval in the berries and must, but must pH was in many PVT concentrations may not necessarily be correlated to cases lower in leaf-pulled treatments. At warmer Oliver, %SS, TA or pH. These results were confirmed in Arkan- BC sites, aroma differences occurred between control and sas by Macaulay and Morris (1993) using V. labruscana leaf-pulled wines for two of four cultivars, and flavour dif- Golden Muscat. ferences were apparent for three of four. Tasters almost Belancic et al. (1997) monitored the effect of sun expo- overwhelmingly indicated that the leaf-pulled treatments sure on the aromatic composition of two Muscat grape contained the most Muscat and/or floral flavour. These cultivars (Muscat of Alexandria and Pink Muscat) over two distinctions could be made based on differences in PVT of seasons in Chile. Fully exposed, semi-shaded (20% shad- 1.45, 0.10 and 0.87 mg/L for Pearl of Csaba, Schönburger ed) and fully shaded (80% shaded) clusters were sampled. and Siegerrebe respectively. Also, in a multiyear experi- Both cultivars contained similar levels of total free terpe- ment testing training system, vine spacing and leaf remov- nols but Muscat of Alexandria was richer in total bound al, basal leaf removal consistently increased both FVT and terpenols. The highest concentration of free terpenols PVT (Reynolds et al. 1996b). These results suggested that was obtained from the semi-shaded treatment, although berry or must monoterpene concentrations may be used as indicators of potential wine varietal character. the differences between exposed and semi-shaded were negligible for Muscat of Alexandria. Shaded grapes had A multiyear project in Ontario found positive effects of the lowest concentration of terpenols, with poor Muscat basal leaf removal and cluster thinning on berry and must typicity. Linalool was the most sensitive to sun exposure. concentrations of FVT and PVT in Chardonnay Musqué Berry temperature was considered critical for maximizing (Reynolds et al. 2007a). Elevated monoterpene concentra- monoterpene concentrations and Muscat flavour in the tions were measured in berries and musts from basal leaf fruit. removal and cluster-thinned plots, but basal leaf removal had by far the greatest magnitude of effect. No differences 3.3 Effects of growing season canopy management on were found in berry FVT across treatments, but basal leaf monoterpenes removal berry PVT were higher than control and thinned A few studies have examined leaf removal effects on samples. Must FVT and PVT concentrations showed dif- monoterpene compounds. Smith et al. (1988) were ferences among treatments with basal leaf removal > clus- among the first to demonstrate the effectiveness of basal ter thinned > control in both cases. There were substantial leaf removal on increasing both monoterpene concentra- differences in sensory profiles of the wines resulting from tion and wine sensory scores of Sauvignon Blanc in New the viticultural practices. Cluster thinning enhanced dry Zealand. fruit aroma and colour and reduced the citrus component to the aroma. Basal leaf removal enhanced citrus aroma Work on Gewürztraminer in British Columbia indicated and lychee and dry fruit flavour. The data also showed that FVT and PVT were responsive to leaf removal, which that regardless of winery treatment (various yeasts and en- could also be increased by cluster thinning and hedging zymes had also been tested), veraison thinning had the (Reynolds and Wardle, 1989a). Neither FVT nor PVT were highest dry fruit aroma. dependent on %SS, TA or pH. In a multisite trial, leaf removal consistently increased berry PVT, and in one year, The use of the glycosyl-glucose (G-G) assay permitted an FVT as well, regardless of site (Reynolds et al. 1996a). assessment of viticultural practices whereby all glucocon- Must FVT and PVT were also increased by leaf removal jugates could be accurately measured by an enzymatic treatment. Increased monoterpene concentration was, in method (Abbott et al. 1993). Target compounds included some cases, associated with lower TA, pH and potassium, monoterpenes, norisoprenoids and some phenolic com- but slightly lower %SS as well. Tasters found more Muscat pounds. Zoecklein et al. (1998a) found higher glycosides – 16 – Impact of Vineyard Management on Grape Maturity

(measured by G-G assay) as well as higher monoterpenes increases, increases in shoot density actually increased and aromatic alcohols in leaf-pulled treatments of Ries- Riesling berry and must PVT. Reducing crop level had ling in Virginia. In a related trial, they found that both a minor effect on PVT concentration. Tasters found 26 the total G-G concentration and the phenol-free fraction shoots/m row wines equal to wines of lesser shoot densi- were highest in leaf-pulled treatments of Chardonnay and ties in terms of sensory quality, despite higher yields. This Riesling (Zoecklein et al. 1998b). The concentrations of may have been due to higher PVT concentration in the total and phenol-free glycosides were higher in Riesling original berries and musts. Some monoterpenes, includ- and Chardonnay fruit from leaf-pulled vs. control vines ing linalool, linalool oxides, -terpineol and citronellol, on three of four harvest dates. Phenol-free glycosides av- were associated with lower crop levels and low to moder- eraged 80% of the total in Riesling juice and 66% of the ate (16 or 26 shoots/m row) shoot densities and increased total in Chardonnay. in concentration during aging.

3.4 Effects of shoot density and crop level on In a similar trial testing Riesling shoot density x cordon monoterpenes age, Reynolds et al. (1994c) found that increasing volume McCarthy and Coombe (1985), McCarthy (1986), McCar- of “old” wood increased berry and must FVT and PVT. thy et al. (1987) and Coombe and Iland (1987) showed Wines produced from vines containing more “old” wood that PVT in Riesling berries were responsive to cluster were higher in floral aroma and flavour, with less vegetal thinning and reduced irrigation in Australia. It was ap- character. Shoot density had less of a magnitude of effect parent that these treatment differences were closely re- than volume of old wood. lated to yield. Eschenbruch et al. (1987) demonstrated A multiyear project in Ontario found positive effects of increases in PVT of Müller-Thurgau berries resulting from crop reduction on berry and must concentrations of FVT cluster thinning and shoot thinning. They concluded that and PVT (Reynolds et al. 2007c) (Fig. 2). The thinning treat- PVT development in that cultivar closely paralleled %SS ments were carried out at five different times during fruit accumulation and hence afforded no better indication of development (bloom, post-set, mid-Stage I, lag phase, ve- ultimate grape and wine quality. They were also unable to raison). Berry FVT increased 10 to 15% over non-thinned demonstrate a clear relationship between PVT concentra- vines in vines thinned at bloom, set and Stage I. Berry PVT tion and wine quality. increased in all thinning treatments except bloom. Both In a Riesling shoot density x crop level trial, Reynolds et FVT and PVT concentrations were lower in must samples al. (1994a, b) showed that despite large yield and shade than in berry samples. Must samples had lowest FVT con-

4.5

3.5

2.5

1.5

1 Potentially volatile terpenes (mg/L)

0.5

0 Late bloom/ Early stage Late stage Lag phase Veraison Non-thinned early set (control) 1999 (*l, ***q) 2000 (***l, q) 2001 (*q) 2002 (***q)

Figure 2. Impact of six thinning times on Chardonnay musqué berry potentially volatile terpene concentration 1999 to 2001. Asterisks indicate significant difference from the control, p< 0.05, Dunnett’s t-test. From Reynolds et al. (2007c). – 17 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

centrations from Stage I and lag phase-thinned vines, and sion, basal leaf removal still reduced TA and increased the lowest PVT in bloom, post-set, Stage I and veraison- PVT, even in the ADC system. This suggests that natural thinned vines. Overall, it was possible to increase the fruit exposure can be augmented by cultural practices to concentration of both FVT and PVT through thinning. increase potential wine quality. Their concentrations were increased by up to 15% and 24% respectively. Non-thinning maximized dry fruit (rai- Zoecklein et al. (2008) found that divided canopies gener- sin, fig) aroma and colour and did not differ from thinning ally produced wines higher in some terpenes and in over- treatments with respect to most other sensory descriptors. all glucoconjugates. Fruit showed consistent differences Bloom thinning maximized citrus (as did veraison thin- in linalool, -terpineol, -damascenone and n-hexanol ning) and grassy aroma. concentrations among training systems. The Smart-Dyson vertically divided system had the highest concentration of 3.5 Influence of training systems on monoterpenes most free volatiles in both juice and wines, while Geneva Numerous training systems are used around the world for double curtain wines frequently had the highest concen- wine grapes. One of the many objectives of a successful tration of phenol-free glycosides. GDC wines generally training system affords optimal fruit exposure that is ap- had higher fruity and floral aromas compared with the propriate for the region in which the grapes are grown. other systems. Enhanced fruit exposure might lead to increased concentrations of aroma compounds. A great many studies have 3.6 Influence of irrigation on monoterpenes, esters and compared the effects of training systems on fruit composi- higher alcohols tion and wine quality. Few irrigation studies have extended their focus to include In British Columbia, a divided canopy system (alternate aroma compounds. Reynolds et al. (2006) showed that double crossarm or ADC) produced yields as high as irrigation deficits applied at veraison resulted in higher 33 t/ha, along with lower TA and higher FVT and PVT concentrations of FVT and PVT in Gewürztraminer than than standard pendelbogen and bilateral cordon systems in early and mid-season deficit treatments (Fig. 4). Re- (Reynolds et al. 1996b) (Fig. 3). Fruit exposure and berry lated floor management treatments (clean-cultivated, to- temperatures were considerably higher in ADC vines than tal herbicide, permanent sod) also produced differences, in bilateral cordon vines. However, despite significant whereby FVT were highest in clean-cultivated treatments increases in cluster exposure resulting from canopy divi- but PVT were highest in sod plots.

3.5

3 a ab b m A 2.5 n n B B c c o no z C C 2 zy zy y y 1.5

1 Potentially volatile terpenes (mg/L) 0.5

0 1988 1990 1991 1992 4-YR. MEAN

Double crossarm Low cordon Lenz Moser Low vee Pendelbogen

The influence of irrigation on grape and wine composition crease most fermentation esters such as isoamyl acetate in was investigated for Agiorgitiko in the Nemea appellation Thompson Seedless. Riesling vines in Washington fertil- area in southern Greece by Koundouras et al. (2006). ized between 0 and 224 kg/ha affected concentrations of Three non-irrigated plots were studied during vintages free and bound monoterpenes in the aged wines (Webster that were very hot and devoid of summer rainfall. Limited et al. 1993). Other compounds, including esters and alco- water availability increased glycoconjugates of the main hols, were also impacted. Generally, most monoterpenes aromatic components of grapes. Wines produced from decreased with increasing fertilization rates, perhaps as a grapes of stressed vineyards were also preferred in tasting shade response, whereas esters and alcohols increased, trials. as a likely effect of increased must amino nitrogen and resultant transamination. Dos Santos et al. (2007) investigated the impacts of partial root-zone drying (PRD) irrigation on Moscatel vine wa- 3.7 Impact of vineyard site on monoterpenes ter relations, vegetative growth, plant microclimate, berry The influence of site on fruit composition is difficult to composition (including aroma compounds) and yield define objectively when site-based differences in canopy components compared to conventional deficit irrigation density, phenology, soil type and cultural practices are in- (50% ETc), full irrigation (100% of ETc) and non-irrigated volved. Di Stefano and Corino (1984, 1986) found only vines. The PRD vines had a better microclimate in the minor differences in terpene concentrations between cluster zone with higher incident photosynthetic photon Moscato Bianco and Moscato Giallo grapes grown on flux density and higher berry temperatures than deficit ir- several sites in the Piedmont and Val d’Aosta regions in rigation and full irrigation. PRD improved berry composi- Northern Italy. Subsequent work (Corino and Di Stefano, tion with higher flavour precursor concentrations, without 1988) showed that higher terpene concentrations were as- any yield reduction compared to deficit irrigation and full sociated with warm sites. Likewise, Noble (1979) found irrigation. few differences between Chardonnay wines whose ori- Vineyard fertilization may have indirect effects on aroma gins included Monterey (Region I), Oakville (Napa Coun- composition. Ough and Bell (1980) in California showed ty, Region III) and Livermore (Alameda County, Region III). that increased fertilization rates between 0 and 440 kg/ Larrechi and Ruiz (1987) and Larrechi et al. (1988) used ha increased concentration of higher alcohols in Thomp- multivariate analysis to distinguish between winegrow- son Seedless wines. Ough and Lee (1981) showed that ing regions in Catalonia, Spain. Ewart (1987) found that increased vineyard fertilization rates could likewise in- a cool, high elevation site (High Eden, South Australia) 3.0 ***Q 2.5

2.0

***Q 1.5 ***I

1.0 ns Monoterpenes (mg/L)

0.5

0 FVT PVT FVT PVT VERAISON HARVEST

Postbloom Lag phase Veraison

Figure 3. Potentially volatile terpene concentration of Riesling berries subjected to five trellising treatments, 1988 to 1992. Bars within years containing different letters are significantly different at p < 0.05, Duncan’s multiple range test. Figure was redrawn from Reynolds et al. (1996b). – 19 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY produced Riesling fruit with the highest terpene concen- A study in a 4 ha Riesling vineyard (Reynolds et al., tration, but terpene concentrations could not be linked to 2007c) was an attempt to resolve the continuing question wine scores. Thus, although great volumes of anecdotal of direct and independent soil and vine vigour effects on evidence exist for differentiating sites, very few objective yield components, berry, must and wine composition and studies have been carried out to quantitate these differ- wine sensory attributes. Monoterpenes were specifically ences. chosen as indicators of fruit maturity and as variables to associate with wine sensory attributes. Geographic infor- Work in British Columbia attempted to distinguish be- mation systems (GIS) delineated spatial variation in soil tween sites based on monoterpene concentrations by lo- texture, soil and vine tissue composition, yield compo- cating vineyards of similar soil type and vine vigour and nents, weight of cane prunings (vine size, an estimate of by maintaining the vines using identical cultural practic- vine vigour) and berry composition including monoter- es. Fruit maturation proceeded faster at Oliver, BC sites penes. Correlations were observed between soil texture on a daily basis, and FVT and PVT were therefore usually and composition vs. berry weight and PVT. However, higher in Oliver berries on any given sampling day (Reyn- there were no consistent soil texture or vine size effects on olds et al. 1995a). Cooler Kelowna, BC sites matured berry, must or wine composition. High vine size increased their fruit more quickly when expressed on a per grow- berry TA, berry PVT and wine FVT and decreased must ing degree–day basis. Oliver musts tended to be higher pH. Sandy soil (vs. clay soil) reduced wine TA and must in FVT and PVT, although harvested at similar TA and pH. PVT and increased berry TA and must %SS. Percent sand Tasters distinguished between wines from the Oliver and was positively correlated in one or more years with sever- Kelowna sites on the basis of aroma for only one of the al variables of potential significance to wine quality: berry four cultivars studied (Reynolds et al. 1995a), but the sites weight, %SS, TA, pH and PVT (Reynolds et al. 2007c). could be distinguished on the basis of flavour for three of Percent clay was also correlated in one or more seasons the four cultivars. For Bacchus and Schönburger, the Oli- with %SS and PVT and inversely correlated with berry ver sites were clearly identified as having the more intense weight, TA and PVT. These results suggest that soil texture Muscat flavour. might play a role in fruit composition and varietal typicity, In a three-site experiment with Gewürztraminer, no clear although non-consistent temporally. No fruit composition pattern emerged regarding the relationship between site variables consistently correlated with vine size, and very and FVT, but berries from both the Oliver and Kelowna few correlative relationships of consequence were dis- sites were highest in PVT in two of five years (Reynolds played except those between vine size and certain yield et al. 1996a). Must FVT and PVT were highest from components. This suggests that vine size, at least in the the Kelowna site. The young wines from the Oliver and range used in this study, does not play a major role in Kelowna sites were identified as most spicy. Aged wines determining fruit composition. from Oliver and Kelowna sites were high in citrus aroma; those from the Kaleden site were primarily vegetative, Other soil or nutritional factors may have an impact on acidic and astringent; and wines from the Oliver site were variables associated with varietal typicity; however, little characterized by butter, cedar and Muscat flavours as well to no work has focused on the impact of vine nutrition as high astringency, aftertaste and body. These results cor- on concentrations of aroma compounds in grapes. Since responded with the PVT concentrations measured in the low berry weight is frequently considered desirable from berry samples taken at harvest. a winemaking standpoint, soil and vine nutritional factors associated with berry weight may also be determinants of 3.8 Spatial variation of aroma compounds the terroir effect. Soil variables found inversely correlated Recently there has been great interest in using geomatic with berry weight (other than soil texture) included pH, tools for the assessment of spatial variation in vineyards, organic matter, P, K, Mg, Ca, CEC and % base saturation including variation in aroma compounds. Elucidation of as Ca; petiole variables included K, Mg and Mn (Reynolds unique spatial patterns for aroma compounds in specific et al. 2007c). Positive soil vs. monoterpene correlations vineyard blocks could lead to the identification of sub- included several with PVT (soil pH, P, K, Ca, Cu, B, CEC blocks of potentially higher value for economic exploita- and % base saturation as Ca) as well as petiole B. Few tion. There might also be implications from this type of studies have found correlations between mineral nutrition study for precision viticulture, if spatial variability in vine and fruit composition, and direct connections between vigour and yield were found to be highly correlated, and soil nutrients and aroma compounds have been difficult if spatial variation in yield were found to be temporally to determine. Webster et al. (1993) found an increase in consistent within individual vineyard blocks. PVT in Riesling with increased nitrogen fertilization, but – 20 – Impact of Vineyard Management on Grape Maturity there was little impact on FVT except where increased related. Soil moisture content was typically higher in clay- vegetative growth lead to greater shading (and thus lower dominated areas of the vineyards, while vine water status FVT). (leaf ) also tended to be higher in clay soils. Leaf  was often inversely correlated with vine size, i.e., vine water Vine size and soil texture did not consistently affect wine status was improved in low vine size areas. Berry weight sensory attributes across vintages (Reynolds et al. 2007c). and %SS were both correlated with vine water status, However, several sensory attributes were affected by vine while TA was inversely correlated. Spatial relationships in size in at least one season. For example, high vine size vine water status appeared to be temporally stable, and decreased mineral aroma and citrus flavour and increased patterns observed in one vintage appeared for the most apple attributes. Clay soil increased mineral aroma and part to be similar in the next despite different weather citrus attributes, but decreased apple aroma. Vine vigour conditions. In addition to these reasonably good spatial and soil texture sometimes affected composition of ber- correlations between soil moisture and leaf , there were ries, must and wines and impacted sensory perception of some excellent spatial relationships between leaf  and aroma, flavour and mouthfeel in wine, but neither vari- both vine size and soil texture. This validates our original able did so consistently (Reynolds et al. 2007c). It must idea that vine size and soil texture are major contributors therefore be concluded that within the scope of this trial’s to terroir. conditions, wine sensory attributes cannot be ascribed to either vine size or soil texture exclusively. Factors other Wines were subjected to sensory analysis. The results sug- than those tested apparently impacted wine sensory at- gest that vine water status may in fact have an influence tributes and hence form much of the basis for so-called on wine sensory attributes. A sorting task was initially terroir effects. performed using expert judges. The judges were asked to group wines in terms of similar sensory characteris- 3.9 The influence of vine water status on spatial tics. Statistical analysis using multidimensional scaling variation in monoterpenes demonstrated that for the most part wines of similar wa- More recently, we have focused on water status as a po- ter status were grouped together. Subsequent descriptive tential determinant of terroir. Mild “water stress” may be analysis showed consistent differences in wines produced beneficial to wine “quality” but sustained water stress can between regions and within vineyards with lower and have many negative consequences, including diminished higher water status. winter hardiness, delayed maturity and reduced yields, 3.10 Impact of pre-fermentation decisions on to name a few. In a trial initiated in 2005, we chose 10 monoterpenes vineyard blocks for each Riesling (and Cabernet Franc in a related study). The main objectives were (1) to ascer- 3.10.1 Harvest date tain the impact of vine and soil water status on aroma Many odour-active compounds clearly continue to ac- compounds and wine sensory attributes, (2) to enumer- cumulate in grape berries long after commercial matu- ate the comparative magnitude of effects of soil texture, rity has been reached. Work by Hardy (1970), Bayonove water status and vine vigour and (3) to elucidate relation- and Cordonnier (1970a) and Gunata et al. (1985) showed ships between these variables and wine sensory quality. that terpenes could increase in fruit long after the point of By meeting these objectives, we intended to elucidate commercial maturity, while Marais and van Wyk (1986) the basis for terroir by integration of several years of soil, and Marais (1987) indicated that delayed harvest of Buket plant nutrition, water relations, yield, fruit composition traube and Riesling, and Gewürztraminer, respectively, and sensory data. led to higher terpene concentrations in musts and wines. In many cases, these differences could be distinguished Using GPS and GIS applied to several vineyards with het- by sensory evaluation. Ewart (1987), on the other hand, erogeneous soil types in Niagara Peninsula, Ontario, we found that wine quality was reduced in late-harvested tested the hypothesis that vine water status plays a major Riesling, even though the late-harvested fruit attained the role in aroma compound concentration and wine sensory highest total terpene concentration. attributes. Riesling data were analyzed by analysis of variance, and GIS-generated maps were analyzed by spatial In a trial in British Columbia, FVT and PVT increased in correlation analysis. In some instances, FVT and PVT three of six V. vinifera cultivars with delays in harvest dates were correlated with leaf water potential () and/or soil between 10 and 20 days (Reynolds et al. 1993). Tasters moisture, suggesting that mild water stress may be benefi- could distinguish between wines from “early” and “late”- cial for wine flavour (Fig. 5 on next page). In most cases, harvested fruit in five of six cultivars based on aroma, and the sand and clay content of the soils were inversely cor- three of the six based on flavour. In many cases, these tast- – 21 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

A-2005 B-2006 C-2007 Riesling 2005 Riesling 2006 Riesling 2007 Château des Charmes Château des Charmes Château des Charmes (Paul Bosc Estate) (Paul Bosc Estate) (Paul Bosc Estate)

N Leaf Water Potential N Leaf Water Potential N Leaf Water Potential (-Bars) (-Bars) (-Bars) 11.32 to 11.51 10.36 to 10.53 11.73 to 11.93 11.51 to 11.70 10.53 to 10.69 11.93 to 12.13 11.70 to 11.90 10.69 to 10.86 12.13 to 12.33 11.90 to 12.09 10.86 to 11.02 12.33 to 12.53 12.09 to 12.28 11.02 to 11.19 12.54 to 12.74 12.28 to 12.47 11.19 to 11.35 12.74 to 12.94 12.47 to 12.66 11.35 to 11.52 12.94 to 13.14 12.66 to 12.86 11.52 to 11.68 13.14 to 13.34 12.86 to 13.05 11.68 to 11.85 13.34 to 13.54 13.05 to 13.24 11.85 to 12.01 13.54 to 13.74

D-2005 E-2006 F-2007 Riesling 2005 Riesling 2006 Riesling 2007 Château des Charmes Château des Charmes Château des Charmes (Paul Bosc Estate) (Paul Bosc Estate) (Paul Bosc Estate)

N Potentially Volatile N Potentially Volatile N Potentially Volatile Terpenes (mg/L) Terpenes (mg/L) Terpenes (mg/L) 2.35 to 2.53 2.70 to 2.89 1.53 to 1.65 2.53 to 2.71 2.89 to 3.09 1.65 to 1.77 2.71 to 2.89 3.09 to 3.28 1.77 to 1.89 2.89 to 3.07 3.28 to 3.47 1.89 to 2.01 3.07 to 3.25 3.47 to 3.66 2.01 to 2.13 3.25 to 3.43 3.66 to 3.86 2.13 to 2.24 3.43 to 3.61 3.86 to 4.05 2.24 to 2.36 3.61 to 3.79 4.05 to 4.24 2.36 to 2.48 3.79 to 3.97 4.24 to 4.44 2.48 to 2.60 3.97 to 4.15 4.44 to 4.63 2.60 to 2.72

Figure 5. GIS-derived maps of the Riesling block on the Paul Bosc Estate, St. Davids, ON, 2005 to 2007. A to C: Leaf water potential, 2005, 2006 and 2007 respectively; D to F: Potentially volatile terpenes (PVT), 2005, 2006 and 2007 respectively. Note how (a) spatial variation in both leaf water potential and PVT are temporally stable across the three seasons; (b) the patterns of leaf water potential and PVT are very similar spatially. These observations suggest that high flavour zones in vineyards are temporally stable and are related to vine water status. Maps are courtesy of Dr. Jim Willwerth. ers indicated that the late-harvested treatments had either Müller-Thurgau, tasters indicated that the press wines had the strongest Muscat and/or strongest floral character. stronger floral character than the free run wines. Concen- trations of FVT and PVT decreased substantially from the 3.10.2. Pressing berry to the juice stage; losses in FVT were 52%, 41% Effective extraction of free terpenes, as well as liberation and 22% for Muscat Ottonel, Gewürztraminer and Kerner of free terpenes from their glycosidic precursors, may respectively, and losses in PVT were 16%, 52%, 13% and be achieved through pre-fermentation practices such as 28% for Müller-Thurgau, Muscat Ottonel, Gewürztramin- skin contact, pressing and the use of enzymes (Cordon- er and Kerner respectively. nier and Bayonove 1981, Strauss et al. 1986, and Reyn- olds et al. 2007a, b). Pressing treatment was shown by 3.10.3. Skin contact Cordonnier and Bayonove (1979) as well as Kinzer and Use of skin contact is controversial among some winemak- Schreier (1980) to have an impact on terpene concentra- ers. Bayonove et al. (1976), Marais and van Wyk (1986), tion in musts. In British Columbia, pressing had no effect Marais (1987) and Marais and Rapp (1988) have indicated on terpenes of Müller-Thurgau, but PVT in press juice of that use of and duration of skin contact can appreciably Muscat Ottonel and Gewürztraminer were higher than in increase the concentration of specific terpenes in must their free run fractions (Reynolds et al. 1993). FVT were and wine. Skin contact increased FVT and PVT in three not affected. Tasters could distinguish between the aromas of four V. vinifera cultivars (Reynolds et al. 1993). Only of Müller-Thurgau and Muscat Ottonel wines made from Siegerrebe produced large enough aroma and flavour dif- free run and press juice. Despite the lack of difference ferences to allow tasters to distinguish between the two between treatments in FVT and PVT concentration in the treatments. There was no clear indication of whether skin – 22 – Impact of Vineyard Management on Grape Maturity contact resulted in more Muscat or floral character in the azines might form largely in the earlier stages of grape aroma or flavour. development, and photo-degradation might be more important in the ripening fruits (Sala et al. 2005).

4. Methoxypyrazines Sauvignon Blanc wines from cooler climates such as New Methoxypyrazines are a group of heterocyclic aromatic Zealand have much higher concentrations than those organic compounds that are naturally present in green from Australia, South Africa or Bordeaux (Allen et al. plant tissue, including grape berries that are associated 1991, 1995; Lacey et al. 1991). In Europe, Kotseridis et al. with green, vegetal or herbaceous characteristics. Impor- (1999) analyzed Merlot and Cabernet Sauvignon wines tant methoxypyrazines found in grapes include 3-isobutyl- from various Bordeaux regions and wine samples from 2-methoxypyrazine (IBMP), 3-sec-butyl-2-methoxypyr- Greece (Xynomavro) for 2-methoxy-3-isobutylpyrazine azine (SBMP) and 3-isopropyl-2-methoxypyrazine (IPMP). concentration. Cultivar, level of maturation and duration Bordeaux cultivars such as Sauvignon Blanc and Caber- of maceration affected the concentration of IBMP. Higher net Sauvignon contain methoxypyrazines at significant humidity and cooler years yield higher IBMP concentra- concentrations and owe much of their distinct aroma to tion in grapes than sunnier and less humid years (Roujou these potent aroma compounds (Bayonove et al. 1975, de Boubée et al. 2000). Kotseridis et al. 1998, and Lacey et al. 1991). IBMP is the Bayonove et al. (1975) reported that a considerable pro- most abundant methoxypyrazine found in grapes (Sala et portion of IBMP resided in grape skins. More recently al. 2000). Bayonove et al. (1975) first reported IBMP in Roujou de Boubée et al. (2002) observed that inside the Cabernet Sauvignon, and subsequent studies (Augustyn berry, IBMP is found mainly in the skin (72%) and seeds and Rapp 1982; Allen et al. 1991, 1995; Lacey et al. (23.8%), and the pulp contains very little (4.2%). 1991; and Kotseridis et al. 1998) identified IBMP, SBMP and IPMP in grape berries and wines. Concentrations in 4.1 Effects of fruit exposure on methoxypyrazines the fruit range from 0 to as much as 42 ng/L (Roujou de Cultural decisions and practices that decrease shading Boubée et al. 2000). and increase fruit exposure should be beneficial in reducing methoxypyrazine concentration in fruit. These include One of the most significant aspects of methoxypyrazines the use of divided canopies, basal leaf removal, cluster is that their sensory thresholds are extraordinarily low. For thinning, deficit irrigation, vine spacing and trellising, example, the human sensory threshold for methoxypyr- hedging and shoot thinning. These practices can produce azines is 1 to 2 ng/L (Buttery et al. 1969a, b). In red wines, a more open, manageable canopy that improves fruit ex- IBMP and IPMP are detected at 10 ng/L (Tominaga et al. posure. A few studies indicate that methoxypyrazines can 1998a, b) and 2 ng/L (Kotseridis et al. 1998) respectively. be manipulated in the vineyard and within the winery. Relatively little is known about the biochemistry of me- In fact, all of the studies targeting manipulation of methoxypyrazines. Consequently there has not been much thoxypyrazine concentration in the vineyard have been literature published about their synthesis or degradation. indirectly due to better fruit exposure. Since vigorous Methoxypyrazine concentrations diminish greatly during canopies that limit sunlight exposure are associated with the berry expansion phase and are relatively high at ve- higher concentrations of methoxypyrazines, good canopy raison, but can decrease dramatically during maturation management can lower these methoxypyrazine concen- from as high as 78 ng/L at mid-veraison to < 2 ng/L at trations. Since methoxypyrazines have been shown to harvest (Lacey et al. 1991). The current belief is that sun- have negative impacts on wine quality at high concentra- light and/or heat can lead to degradation of pyrazines. Al- tions, studies have focused on minimizing methoxypyr- len et al. (1991) showed a decrease in methoxypyrazine azines in grapes and wine. Research seems to indicate concentrations in grapes via photodecomposition due to that conditions during grape maturation are primarily re- sunlight. Hashizume and Sumuta (1999) showed that light sponsible for the methoxypyrazine concentration in wines exposure has two opposite effects on the concentration of (Allen et al. 1991, 1995; Lacey et al. 1991; Roujou de methoxypyrazines in grapes: (a) promoting the formation Boubée et al. 2000). Shade seems to have a major effect of methoxypyrazines in immature grapes and (b) non-enon methoxypyrazine concentrations in grapes. Exposed zymatically photo-decomposing the methoxypyrazines in clusters can have three times lower concentrations of me- ripening grapes. A balance between biological formation thoxypyrazines than shaded fruits (Roujou de Boubée et and photo-degradation may determine the methoxypyr- al. 2000). Sala et al. (2004), however, found that during azine concentration in grapes throughout the ripening ripening, IBMP concentrations in grapes exposed to sun- process (Roujou de Boubée et al. 2000). Methoxypyr- shine were not different from those covered with pieces of – 23 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY sackcloth. Nonetheless, clusters protected from sunlight samples than non-irrigated and lower plantation density from the beginning of veraison resulted in wines with a vines. substantially lower concentration of this compound than 4.6 Impact of pre-fermentation decisions on the control samples. methoxypyrazines 4.2. Effects of growing season canopy management on Methoxypyrazines are very stable compounds due to their methoxypyrazines chemical nature and therefore are very difficult to remove It has become clear that methoxypyrazine concentra- or reduce in wines. The use of oak can reduce vegetal/her- tions can be reduced by canopy management. Arnold and baceous aromas/flavours in wines with high methoxypyr- Bledsoe (1990) in California showed that severe fruit zone azine concentrations by a straight masking effect. Aiken leaf pulling reduced vegetal sensory descriptors in Sau- and Noble (1984) found that “vegetal” characteristics vignon Blanc, suggesting that the leaf pulling treatments decreased in Cabernet Sauvignon wines after oak aging. had reduced methoxypyrazines. The canopies in question Pickering et al. (2006) found that treatment with oak chips were manipulated using several leaf removal treatments. reduced the intensity of “ladybug taint” (Pickering et al. Leaves were removed on three different occasions at three 2004), which is a taint associated with high concentra- severity levels, whereas control grapevines received no tions of IPMP. Methoxypyrazines are highly extractable in leaf removal. Descriptive sensory analysis showed large wines (Roujou de Boubée et al. 2002). Since a majority differences among the wines for two vegetal aromas (cel- of methoxypyrazines are found in grape stems and skins, ery/fresh vegetable and canned green bean) as well as the limited skin contact and exclusion of stems or leaves from vegetal-flavour-by-mouth. The greatest reduction in the the winemaking process can reduce the amount of me- vegetal components was found with the middle timing/ thoxypyrazines extracted into the resultant wines. Lighter most severe leaf removal treatment. Early, severe leaf re- pressing regimes can also reduce methoxypyrazine con- moval was nearly as effective as the middle timing treat- centrations. Press wines contain higher concentrations of ment in reducing vegetal flavours, but late, severe leaf methoxypyrazines (Roujou de Boubée et al. 2002). This removal was not. Fruit composition was also altered, %SS suggests that a fraction of methoxypyrazines is extracted were increased and TA was reduced in the leaf pulled from the skins during rigorous pressing. Settling and clari- treatments (Bledsoe et al. 1988). fying white wine must decreases methoxypyrazine concentration in half (Roujou de Boubée et al. 2002). They 4.3 Effects of shoot density and crop level on demonstrated that thermovinification could also be use- methoxypyrazines ful by reducing IBMP from 29 to 67%. However, heating The effect of crop level on methoxypyrazines has heretofore wines is not widely practised in premium wine produc- not been a well-researched topic. Crop thinning (Marais tion. Since it can be shown that winemaking procedures 1994, and Chapman et al. 2004a, b) can also help de- probably have a minimal impact on pyrazine concentra- crease methoxypyrazine concentration in grapes because tions, it is most appropriate to focus on viticulture prac- excessive crop-to-leaf area can delay the rate of fruit ma- tices and methoxypyrazine management. turity and therefore the degradation of methoxypyrazines.

4.4 Influence of training systems on methoxypyrazines 5. Norisoprenoids As in the case of fruit exposure and basal leaf removal, Norisoprenoids are C13 degradation products of carot- certain training systems may enhance fruit environment enoids (b-carotene and lutein). The norisoprenoids accu- and potentially lead to changes in methoxypyrazine con- mulate during Stage III of berry growth much the same as centration. Nonetheless, Sala et al. (2004) found that go- the terpenes. Whereas the Muscat and floral cultivars owe belet- and bilateral-cordon-trained Cabernet Sauvignon their character to terpenes and the Bordeaux types to pyr- vines did not produce fruit with different berry IBMP azines, the norisoprenoids are more ubiquitous and add concentrations. However, IBMP concentration of the final nuances to many cultivars across a wide range of regions. wines was much higher in the cordon-trained vines. They are usually found as glucosides and hence represent a pool of flavour reserves in developing grapes. Typical 4.5 Influence of irrigation on methoxypyrazines compounds include β-damascenone (megastigma-3,5,8- Few studies exist that have addressed irrigation effects on trien-7-one), vitispirane (6,9-epoxy-3,5(13)-megastigma- methoxypyrazines. Sala et al. (2005) found that irrigated diene), 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN), vines and vines planted at a higher plantation density actinidol, vomifoliol, etc. Their aroma character varies had significantly higher concentrations of IBMP in berry from leafy, minty and fruity through various floral charac- – 24 – Impact of Vineyard Management on Grape Maturity ters. Many of our common wine grapes such as Chardon- ever, the higher monoterpene glycoconjugates in these nay owe much of their character to groups of norisopren- berries were likely related to their early maturity. Authors oids. The typical violet aroma of Syrah is due to specific concluded that under their experimental conditions, berry norisoprenoid compounds. aroma composition did not appear to be affected by foliage shade. In a related study using the same experimental The carotenoid pigments all have squalene as an interme- protocol, Bureau et al. (2000b) looked at the effects of diate, and hence these and the terpenes share a common the modification of vine or cluster environment on glyco- pathway up as far as geranyl pyrophosphate. The carot- conjugates in Syrah berries. Vines were shaded from berry enoids form by the condensation of two GPP molecules set to maturity, with black polyethylene nets of different to form geranyl-geranyl pyrophosphate, which then goes mesh size to obtain 30 and 50% of the direct sunlight. through a few steps (prephytoene lycopersene phy- k k Clusters were naturally shaded by the leaves or artificially toene, followed by cyclization b-carotene). k with 90% shade bags. Sun-exposed berries were chosen 5.1. Effects of fruit exposure on norisoprenoids as control berries. A decrease in glycoconjugates was ob- Enhanced light and temperature environments can lead to served in shaded clusters, particularly for phenolic and C -norisoprenoidic glycosides. In the same way, vine breakdown of carotenoid pigments and consequently high- 13 shading caused a decrease in the concentrations of glyco- er concentrations of norisoprenoids (Martais et al. 1992). sides of terpenols, phenols and C norisoprenoids in ber- However, in many cases the impact of light exposure and/ 13 ries, but the grape environment (microclimate) affected or cluster temperature has been inconsistent at best. Ra- the berry composition more than the vine environment. A zungles et al. (1998) were among the first to study light and cluster thinning experiment confirmed the independence temperature effects on C13 norisoprenoids. Sunlight effects of grapes with regard to the plant for the biosynthesis of on the berry carotenoid and C13 norisoprenoid composi- the C -norisoprenoid glycosides. tion were studied before and after veraison. Syrah berries 13 that were sun-exposed before veraison were higher in ca- The effect of cluster exposure on the grape carotenoid rotenoids than shaded berries. However, after veraison, profile was also investigated by Oliveira et al. (2004) sunlight caused the degradation of these pigments. Sunlight on several Portuguese cultivars. Grape cultivar, ripeness modified the non-epoxyxanthophyll/epoxyxanthophyll ra- stage, sunlight and shade exposure, altitude and vegeta- tios. Metabolic relationships between the glycosylated C13 tive height were all the variables studied. Differences be- norisoprenoids and their potential precursors were tenta- tween cultivar were observed in eight different red wine tively established between certain C13 norisoprenoids and grape cultivars: Touriga Brasileira, Tinta Barroca, Tinta carotenoids in specific sun-exposure treatments. In ad- Amarela, Souzao, Touriga Franca, Touriga Nacional, Tinta dition, the sunlight increased other glycosidically bound Roriz and Tinto Cao, from the Douro region. Tinta Amare- compounds such as monoterpenes and phenols. la and Touriga Brasileira produced higher concentrations of carotenoids. Carotenoids decreased during ripening. Effects of the modification of whole vine or individual Decreases of lutein were observed until 66% of the origi- cluster light environment by shade cloth from berry set nal concentration, whereas -carotene slowly decreased to maturity were studied by Bureau et al. (2000a) on in a constant manner until the harvest date. Carotenoids the volatiles and glycoconjugates in Muscat of Frontig- were consistently higher in shaded grapes than in those nan berries. Whole vines were shaded with 50 and 70% exposed to direct sunlight in two white grape cultivars, shade cloth, while clusters were shaded with 90% shade Maria Gomes and Loureiro. cloth. The sun-exposed berries were chosen as control berries, and the berries naturally shaded under foliage Lee et al. (2007) assessed the effects of light exposure and were also studied. The natural shading of clusters under vine microclimate on C13-norisoprenoid concentrations foliage did not decrease the concentrations of free and in Cabernet Sauvignon grapes and wines by measuring bound compounds compared to sun-exposed berries. The the amounts of -damascenone, TDN and vitispirane. The artificially shaded clusters had lower concentrations of most exposed treatment (all lateral and primary leaves C13 norisoprenoids (as well as monoterpenes) than both removed) had the highest light intensity and temperature sun-exposed berries and berries from naturally shaded and showed the highest concentrations of TDN and vi- clusters. Moreover, the effect of vine shading on the aro- tispirane. However, in the more shaded treatments, con- ma composition was lower compared to artificial cluster centrations of all norisoprenoids were variable and de- shading. Decreasing the cluster number per vine did not pendent on the treatment conditions. When leaves were influence the total amounts of glycosidically bound com- removed, C13-norisoprenoid concentrations were linearly pounds, except for monoterpene glycoconjugates. How- and positively correlated with increasing sunlight expo- – 25 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY sure. In contrast, in the most shaded treatments with no fertilization led to lower TDN concentrations, whereas leaf removal, there were high concentrations of noriso- the trend was for actinidol and -damascenone to in- prenoids. -Damascenone concentrations were highest crease with increasing fertilization, and for vitispirane to when no leaves were removed. Grapes and correspond- be unaffected by fertilization. Yield, which was affected ing wines from the south side of the vine had higher nor- by fertilization, showed negative correlations with noriso- isoprenoids than those from the north side. prenoids. Vitispirane, actinidol and TDN increased with storage time. The coolest year studied, which had fewest Ristic et al. (2007) enclosed clusters of Shiraz grapes prior sunshine hours, resulted in the highest concentrations of to flowering in boxes designed to eliminate light without -damascenone and the lowest concentrations of vitispi- altering bunch temperature and humidity. This artificial rane, actinidol and TDN. shading had little effect on berry ripening and accumulation of %SS but at harvest, the shaded clusters had smaller berries, pH and TA. Analysis of potential flavour 6. Volatile Thiols compounds indicated that the wines made from shad- Volatile thiol compounds are currently one of the most ed fruit had decreased concentrations of glycosides of active areas of wine flavour research. They are found in -damascenone and TDN. Sensory analysis of the wines small quantities in grapes, and most certainly their precur- indicated no difference in aroma attributes, but the wines sors might be influenced by viticultural practices. They are made from shaded fruit were rated lower for astringency, among the most potent aroma compounds found in wine. fruit flavour and flavour persistence in mouth. These sulphur-containing compounds have extremely low perception thresholds, ranging from 0.8–1500 ng/kg 5.2 Influence of irrigation on norisoprenoids (Tominaga et al. 2000). Currently, five highly aromatic vol- The limited information we have on the response of nor- atile thiols—4-mercapto-4-methylpentan-2-one (4MMP), isoprenoids to irrigation suggests that deficit irrigation 3-mercaptohexyl acetate (A3MH), 4-mercapto-4-methyl- might lead to increases in norisoprenoid concentration. pentan-2-ol (4MMPOH), 3-mercaptohexan-1-ol (3MH) The influence of irrigation strategy on grape berry carot- and 3-mercapto-3-methylbutan-1-ol (3MMB)—have been enoids and C13-norisoprenoid precursors was investi- identified in grapes (Darriet et al. 1995, and Tominaga et gated for Cabernet Sauvignon by Bindon et al. (2007) in al. 1998a, b, 2000). The compounds 4MMP, 4MMPOH Australia. Two irrigation treatments were compared, one and 3MH have aromas characteristic of box tree/broom, in which vines received reduced irrigation applied alter- citrus zest and grapefruit/passion fruit respectively (Tomi- nately to either side of the vine (partial rootzone drying, naga et al. 1998b, 2000). Moreover, 3MMB and A3MH PRD) and a second control treatment in which water was are responsible for the overtones of cooked leeks and pas- applied to both sides of the vine. The PRD vines received sion fruit respectively (Tominaga et al. 2000). These com- on average 66% of the water applied to the controls. In pounds impact varietal character in certain grapes and both irrigation treatments, the most abundant grape berry wine. For example, they play a major role in the aroma carotenoids, -carotene and lutein, decreased post-verai- of Sauvignon Blanc (Darriet et al. 1995, and Tominaga et son, but as the fruit approached maturity, the concentra- al. 1998b, 2000), Cabernet Sauvignon (Tominaga et al. tion of these carotenoids increased in fruit of PRD-treated 1998a) and Merlot (Murat et al. 2001a) wines. Further- vines relative to the controls, particularly for lutein. More- more, Tominaga et al. (2000) found that these aroma com- over, PRD caused increases in the concentration of hy- pounds are also responsible for nuances of several other drolytically released C13-norisoprenoids -damascenone, V. vinifera cultivars including Semillon, Gewürztraminer, -ionone and 1,1,6-trimethyl-1,2-dihydronaphthalene in Riesling and Colombard. fruit at harvest. During the second season of the experi- Darriet et al. (1995) showed that 4MMP and 3MH exist ment, the effect of the PRD treatment on C13-norisopren- in grapes but in the form of non-volatile, cysteine-bound oids was greater, and there was an increase in total C13- conjugates. Peyrot des Gachons (2000) found that the norisoprenoid content per berry, suggesting that increases cysteinylated precursors for 4MMP and 4MMPOH are in C13-norisoprenoids in response to PRD were indepen- located mainly in grape juice, while the precursor for dent of water deficit–induced changes in berry size and 3MH is distributed equally between berry skin and juice. concomitant altered berry surface-area-to-volume ratios. Their location does not depend on the stage of berry de- Linsenmeier and Löhnerz (2007) measured C13-noriso- velopment (Peyrot des Gachons 2000). The biosynthesis prenoids in Riesling wines produced from the 1996, 1997 of these S-cysteine conjugates in grapevines is virtually and 2003 vintages within the scope of a long-term nitro- unknown. It is thought that these compounds are inter- gen fertilization experiment (0, 60 and 150 kg N/ha). N mediate products in the detoxification system of living – 26 – Impact of Vineyard Management on Grape Maturity organisms and are formed from the breakdown of the cor- 3MH in wines with the presence of oxygen and catechin. responding S-glutathione conjugates (Peyrot des Gachons However, sulphur dioxide reduced these effects consid- 2000). Although volatile thiols are almost non-existent in erably. Anthocyanins can help stabilize volatile thiols in grapes and must (Peyrot des Gachons et al. 2000, 2005), wine (Blanchard et al. 2004). Oak aging can be used to they are released into wine from their corresponding pre- manipulate the composition and amount of volatile thiols cursors during alcoholic fermentation (Howell et al. 2004, present in wine; 2-furanmethanethiol (2FM), a thiol with and Murat et al. 2001b). a strong roast coffee aroma, has been identified in certain red Bordeaux wines and has been found in toasted oak Since volatile thiols are a new area of research and have staves (Tominaga et al. 2000). only recently been identified and quantified, there is little research on how these compounds can be altered in the Only recently have volatile thiols been a key area of re- vineyard or winery. Peyrot des Gachons et al. (2005) found search in wine flavour chemistry. Research thus far has that volatile thiol precursors were highest in vines with focused mainly on method development for identification moderate nitrogen supply, whereas nitrogen deficiency and quantification of these compounds and their contri- seemed to limit aroma potential. Furthermore, they found bution in certain key cultivars such as Sauvignon Blanc that volatile thiol precursors were highest in vines under and Cabernet Sauvignon. There are ongoing studies look- mild water deficit, whereas severe water deficit stress ing at ways to release volatile thiols from their cysteinyl- seemed to limit aroma potential. Therefore, highest aroma ated precursors by yeast strains. Generally speaking in potential can be achieved under mild water stress and oenology and viticulture, any aspect concerning volatile when nitrogen status is non-limited (Peyrot des Gachons et thiols is a wide-open research topic. Research is currently al. 2005). Powdery mildew infection on berries decreases ongoing in places such as New Zealand, where it is felt the concentration of 3MH (Calonnec et al. 2004). that these compounds contribute more than just nuances to their wines. In the case that volatile thiols are in fact the As mentioned, 4MMP and 3MH (and perhaps other vola- most potent compounds in wines, practices in the vine- tile thiols) exist in grapes in the form of non-volatile, cys- yard can be further explored to maximize aroma potential teine-bound conjugates. It is suggested that the amplifica- from these compounds. tion of these aromas during fermentation occurs through the action of yeast carbon-sulphur lyases (Tominaga et al. 1998a, b, and Howell et al. 2004). The compounds 4MMP, 7. Effects of Viticultural Practices on Phenolic 4MMPOH and 3MH are released into wine from their Analytes grape-derived cysteinylated precursors during alcoholic 7.1 Fruit exposure effects on phenolic analytes fermentation (Darriet et al. 1995, Tominaga et al. 1998a, There is considerable evidence that anthocyanin produc- b, and Peyrot des Gachons et al. 2000, 2005). Therefore, tion is positively correlated with light levels, both on the it appears that volatile thiols might be manipulated easily canopy in general (Kliewer 1970, 1977; Keller and Hrazdi- in the winery by release of these thiol compounds from na 1998; and Spayd et al. 2002) and on the fruit specifical- their precursors. Various yeast strains can produce varying ly (Spayd et al. 2002). Other results have been either more amounts of each of the compounds (Murat et al. 2001b, complicated or entirely contrary to these results, suggest- and Howell et al. 2004). Fermentation temperature also ing that there may be varietal differences in the synthesis of has an influence on the release of thiol compounds. anthocyanins. Among those who have conducted studies Howell et al. (2004) found that at 28°C some yeast strains using artificial shading, Kataoka et al. (1984) found that released 100-fold more 4MMP than at 18°C. Although complete shading (in an aluminum foil bag) of Kyoho clus- only small amounts (1.4 to 4.2%) of aroma precursors ters during ripening resulted in inhibited phenylammoni- are transformed during alcoholic fermentation (Peyrot des um lyase (PAL) activity and no anthocyanin accumulation Gachons et al. 2000, and Howell et al. 2004), these con- in the berries. The same experiment found that complete centrations of volatile thiols still contribute significantly to shading of Super Hamburg berries had little or no effect the overall sensory profile of the resultant wine. on PAL activity nor on anthocyanin synthesis. Likewise, Following primary fermentation and malolactic fermen- Downey et al. (2004) found that shading clusters inside tation, thiol concentrations can be considerable (rela- opaque boxes had no effect on anthocyanin accumula- tively speaking). However, thiols can be easily oxidized tion in Shiraz berries in two of three years. Differences after certain winemaking procedures such as racking or occurred between shade and exposed fruit in the relative aging, so these compounds can decrease significantly. accumulation of different anthocyanins; shaded fruit con- Blanchard et al. (2004) found a substantial decrease in tained relatively more peonidin and cyanidin glucosides. – 27 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

Condensed tannins were not affected by shading, but fla- also affects fruit colouration. Day-night temperature dif- vonols were reduced by shading. Similarly, Yamakawa et ferences of greater than 10ºC were generally found to be al. (1983) found considerable anthocyanin accumulation inhibitory to fruit colouration, beyond the detrimental ef- in Vitis cell suspension in the absence of light, but light fects of high temperature on colouration. irradiation enhanced anthocyanin accumulation. Bergqvist et al. (2001) assessed the effects of sunlight ex- Cortell and Kennedy (2006) examined changes in flavo- posure and related temperature effects on phenolic ana- nols, proanthocyanidins and anthocyanins in Pinot Noir lytes in addition to berry growth and composition of Cab- in Oregon in shaded and exposed treatments. Light exclu- ernet Sauvignon and Grenache. Anthocyanins increased sion boxes were installed on pairs of clusters on the same linearly as sunlight exposure on the north side of the shoot (shaded treatment), while a second set of clusters on canopy increased, but declined when cluster exposure on an adjacent shoot were considered as the exposed treat- the south exceeded 100 mmol m-2 sec-1. Total phenols ment. Cluster shading resulted in a substantial decrease generally followed a similar pattern. The results suggest in flavonols and skin proanthocyanidins and minimal that the effects of light on fruit composition, including differences in anthocyanins. Shaded and exposed treat- phenolic analytes, are heavily dependent on the extent to ments were similar at veraison in terms of seed proan- which berry temperature is elevated because of increased thocyanidins; however, by harvest, the shaded treatment sunlight exposure. The authors concluded that prolonged had higher extension and terminal subunits compared to exposure of clusters to direct sunlight should be avoided the exposed treatment. Shaded fruit was lower for all skin for maximum berry colour in the central San Joaquin Val- proanthocyanidins at both veraison and harvest. Shading ley and other warm regions. caused an increase in the proportion of (-)-epicatechin In Piedmont, Italy, Chorti et al. (2007) assessed five fruit and a decrease in (-)-epigallocatechin at harvest in berry exposure levels to Nebbiolo: vines exposed to normal skins. Seed proanthocyanidins in shaded fruit contained light conditions throughout the season; fruit-zone shaded a lower proportion of (+)-catechin and a higher propor- vines from fruit-set to veraison; fruit-zone shaded vines tion of (-)-epicatechin-3-O-gallate and a lower propor- from fruit-set to harvest; fruit-zone shaded vines from tion of (+)- catechin and (-)-epicatechin-3-O-gallate and veraison to harvest; and fruit-zone leaf-removed vines a higher proportion of (-)- epicatechin. For anthocyanins, at fruit-set. Fruit-zone shading during the initial phase of the shaded treatment had proportional reductions in del- berry development decreased berry size and consequent- phinidin, cyanidin, petunidin and malvidin and a large ly impacted concentration of many analytes. Fruit-zone increase in peonidin glucosides. Model wine extractions shading delayed accumulation of %SS, and when applied from the two treatments paralleled differences in the fruit from veraison to harvest, reduced total anthocyanin con- with a lower concentration of flavonols, anthocyanins and centration, but it did not affect total flavonoid accumula- proanthocyanidins in the shaded treatment, while the skin tion. Cluster-zone leaf removal notably increased cluster proanthocyanidin percent extraction was 17% higher in exposure and decreased total anthocyanin and total flavo- the exposed model extraction than the shaded treatment. noid accumulation. Among those assessing natural canopy sun and shade Spayd et al. (2002) succeeded in identifying how light and conditions, Crippen and Morrison (1986b) found differ- temperature affect phenolic analytes in different ways. ences between sun-exposed and shaded Cabernet Sau- Anthocyanin and phenolic profiles of berry skins from vignon fruit in terms of soluble phenol content per berry Merlot in the Yakima Valley of Washington were exam- and in both anthocyanin concentration and total content ined in terms of the individual influences of sun exposure per berry pre-harvest. There were no differences at har- and temperature. West-exposed clusters were cooled to vest, however. Total soluble phenols increased until verai- the temperature of shaded clusters, and shaded clusters son and then decreased from veraison to harvest. The per- were heated to the temperature of west-exposed clusters. centage of polymerized phenols decreased during early Berry temperature was increased as much as 13ºC above berry growth and then increased from veraison to harvest. ambient and shaded cluster temperatures when clusters Temperature has also been found to affect anthocyanin were exposed to sunlight, regardless of aspect. However, production in grape berries. In general, high temperatures maximum fruit temperatures were higher for clusters on (above 35ºC) have been inhibitory to anthocyanin synthe- the west side of the canopy (often > 40ºC) because am- sis (Kliewer 1970, 1977; Kliewer and Torres 1972; Katao- bient temperatures were higher after noon. East-exposed ka et al. 1984; and Spayd et al. 2002). Kliewer and Torres clusters had higher total skin monomeric anthocyanin (1972) also determined that diurnal flux in temperature (TSMA) concentrations than west-exposed or shaded clus- – 28 – Impact of Vineyard Management on Grape Maturity ters. Exposure to sunlight increased TSMA concentrations related to the higher exposure and temperatures found in regardless of temperature. Cooling sun-exposed clusters Site B compared to Site A, which were found also in the increased TSMA concentrations, while heating shaded low vigour zones. clusters decreased TSMA in warm seasons, but had no ef- It is reasonable to assume that significant enzymes respon- fect in cooler ripening seasons. Ultraviolet (UV) light bar- sible for anthocyanin and phenol synthesis are up-regu- riers did not influence either cluster temperature or TSMA lated by enhanced light and temperature environments. concentrations, and lower TSMA concentrations in berry Downey et al. (2004) focused exclusively on light effects skins from west-exposed clusters were due to temperature and not to UV radiation. Exposure to solar radiation in- on the synthesis of phenolic analytes and the genes en- creased concentrations of the 3-glycosides of quercetin, coding those enzymes responsible. Opaque boxes were kaempferol and myricetin. Sun-exposed clusters, regard- applied to clusters of Shiraz grapes prior to flowering to less of aspect, had almost 10 times greater concentrations determine the effect of sunlight on berry development and of total flavonols than shaded clusters. UV-light barriers accumulation of flavonoids. The boxes were designed in reduced individual and total flavonol concentrations, sug- particular to exclude light and to minimize changes in gesting that their synthesis might be partly light driven; temperature and humidity. There was no effect of shad- temperature had little to no effect on their concentrations. ing on sugar accumulation and berry weight. Chloro- phyll concentration was lower in the shaded fruit, which Few of the aforementioned studies have investigated the im- appeared pale yellow until veraison. The fruit coloured pact of vine shading on the sensory attributes of the resul- normally in the shaded clusters, and in two of three sea- tant wine. A study in the Sunraysia region, Victoria, Australia sons there was no change in anthocyanin concentration. examined the effects of canopy exposure levels on phenolic Anthocyanin composition was altered in the shaded fruit, composition plus aroma, flavour and mouthfeel aspects in which had a greater proportion of the anthocyanins cyani- Cabernet Sauvignon and Shiraz wines whose source vines din and peonidin glucosides. Shading had no effect on the were subjected to different levels of canopy exposure (Jos- concentrations of condensed tannins in the skin or seeds celyne et al., 2007). Canopy exposure treatments included of ripe fruit, but it reduced flavonols in the skin. In the a control (standard vineyard practice), exposed (achieved exposed fruit, flavonol concentration was highest around with a foliage wire 600 mm above the top cordon), highly flowering then declined as the berries grew, but there exposed (using a foliage wire with leaf plucking in the fruit was an increase in flavonols per berry during ripening. zone) and shaded treatment (using 70% shade cloth). Spec- When the boxes were applied before flowering, shaded tral and descriptive analyses showed that anthocyanins, fruit had much lower concentrations of flavonols through- other phenolics and perceived astringency were lower in out berry development, and at harvest the flavonols were wines made from shaded fruit; however, the reverse was < 10% that in exposed fruit. The authors mentioned two generally not observed in wines of exposed and highly ex- key genes that appeared to be up-regulated during berry posed fruit. Descriptive analysis also showed wines from development: Expression of the gene encoding UDP- the shaded fruit were different from other treatments for a glucose flavonoid-3-O-glucosyl transferase, a key gene in number of flavour and aroma characters. anthocyanin synthesis, increased after veraison and was Another aspect given little attention in the literature is that similar in both shaded and exposed fruit. Secondly, a gene of spatial variability in fruit exposure resulting from differ- encoding flavonol synthase was expressed at flowering ent vine vigour levels, and the relationship between vigour and during ripening in exposed grapes, but its expression and phenolic analytes. Cortell et al. (2007) examined was reduced in shaded fruit. The authors suggested that fruit exposure effects on Pinot Noir anthocyanins from a shading had little effect on berry development and ripen- standpoint of vigour-induced fruit exposure effects. High ing, including accumulation of anthocyanins and tannins, vigour zones in two vineyards had lower %SS and higher but as Spayd et al. (2002) indicated, shade substantially TA, and there was a trend for lower anthocyanin concen- decreased flavonol synthesis. tration in the high vigour zones. In one year, there was a higher proportion of malvidin-3-O-glucoside and lower 7.2 Growing season canopy manipulation proportions of the other four anthocyanins (delphinidin-, Many studies have also been done on the effects of can- cyanidin-, petunidin- and peonidin-3-O-glucosides) com- opy manipulation on red winegrape composition (Smith monly found in Pinot Noir. In both years studied, one site et al. 1988 and Reynolds et al. 1994c, 1995b, 1996c). had proportionally higher peonidin-3-O-glucoside and Among research into growing season canopy manipula- lower malvidin-3-O-glucoside than the other site. Authors tion, a New Zealand study unequivocally found that basal opined that some of these differences might have been leaf removal (either 50% or 100% of leaves in fruit zone) – 29 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY increased both total phenol and anthocyanin concentra- reduced substantially but colour was reduced to a lesser tions in Cabernet Sauvignon, with the greatest increase degree than by increasing canopy density (Reynolds et al. (≈50% over control) occurring when the treatment was 1994c). In Scott Henry wines, TA and pH were reduced done five weeks after flowering (Smith et al. 1988). Maz- and ethanol and anthocyanins were increased. Ethanol za et al. (1999) also found that leaf removal resulted in and wine TA increased and pH decreased with increasing higher phenolic concentration and colour density over shoot density. Reducing crop level increased ethanol and the control. Conversely, Iacono et al. (1994) found that anthocyanins. Clove, bell pepper and grassy aromas were when 40% of basal leaves were removed from around the least in 10 shoots/m and Scott Henry treatments. Reduc- grape clusters, there was a reduction in %SS, no change ing crop level increased colour, currant aroma, astringen- in malic or tartaric acid and no change in anthocyanins, cy and intensity of finish independent of canopy treatment even though available radiation to the clusters was dra- (Reynolds et al. 1996b). matically increased above the control. Shading of the en- Reynolds et al. (2005) explored delayed shoot thinning tire canopy (with a 50% shade cloth), on the other hand, as an alternative to canopy division in vigorous canopies. lowered the anthocyanin concentration across all canopy Pinot Noir and Cabernet Franc vines in Ontario were treatments (cluster thin and leaf removal). Leaf removal subjected to six different shoot-thinning timings between reduced the shading of clusters but also reduced photo- Eichhorn and Lorenz phenological stages 9 to 31. An addi- synthetic capacity, resulting in lower sugar concentrations tional treatment (double pruning retaining two disposable and no differences in anthocyanins or acidity. Among canes) was imposed on Cabernet Franc. Many of these canopy manipulation resulting in negative consequences, treatments resulted in improved canopy microclimate, late-season and/or severe hedging was shown to reduce e.g., treatments imposed after bloom plus the double- anthocyanins in De Chaunac grapes in British Columbia pruned treatment produced lower leaf layer numbers and (Reynolds and Wardle 1989c). better leaf and cluster exposure than did the control and

7.3 Crop control early shoot thinning in Cabernet Franc, while early shoot- thinning treatments induced higher leaf areas in both cul- Many studies have also been done on the effects of crop tivars compared to later treatments. Early shoot thinning reduction on red winegrape composition (Weaver et al. on Pinot Noir increased TA and %SS in berries and must. 1961, Kliewer and Weaver 1971, Ough and Nagaoka Early shoot thinning on Cabernet Franc increased colour 1984, and Reynolds et al. 1994c). A few studies (Iacono intensity in berries and colour intensity, total phenolics et al. 1994, Reynolds et al. 1994c, and Mazza et al 1999) and total anthocyanins in wines. The double-prune treat- have also been done on the effects of both canopy and ment was characterized by higher %SS, hue/tint, colour crop manipulation on red winegrape maturity in terms of intensity and total phenolics overall. %SS, TA, pH and aroma and colour compounds. Studies with V. vinifera red wine cultivars in which the crop was 7.4 Training systems and vine spacing adjusted by means of cluster thinning alone have found As with growing season canopy management, choice of a that crop reduction results in increased %SS, anthocya- training system may have a substantial impact on leaf and nins, total phenols and colour intensity (Reynolds et al. cluster microclimate, and consequently, fruit composition 1994c, Mazza et al. 1999, and Guidoni et al. 2002). The and wine quality. These effects on red winegrape cultivars effectiveness of crop reduction has not always been con- extend to phenolic analytes. Smart (1982) and Smart et al. sistent. Some have found no differences in must composi- (1985b) described the effects of GDC training on reduction when crops were thinned (Ough and Nagaoka 1984) tion of canopy shading in Shiraz vines, and ultimately the whereas others have found specific fruit composition at- enhancement of ionized anthocyanins and total phenols. tributes to be more affected than others. Crop reduction Carbonneau and Huglin (1982) and Carbonneau et al. may also have beneficial effects on individual phenolic (1978) described the positive impacts of the various itera- analytes as well (Di Profio et al. 2011). tions of the Lyre divided canopies on berry skin anthocyanins and total polyphenols in Cabernet Sauvignon, along One study with Pinot Noir conducted in British Colum- with corresponding enhancements in wine quality. bia and Oregon involving three canopy management treatments (vertical shoot positioning with either 10 or Reynolds et al. (1994c) tested Scott Henry training against 20 shoots/m row, Scott Henry [vertical canopy division] vertically shoot-positioned canopies (10 and 20 shoots with 10 shoots/m canopy, 15 shoots/m row in Oregon per m row) on Pinot Noir vines in British Columbia. Scott only) in combination with two crop levels (full crop, half Henry–trained vines had the lowest weight of cane prun- crop) found that by increasing the crop level, %SS were ings and highest crop loads, and also had lowest %SS, pH, – 30 – Impact of Vineyard Management on Grape Maturity anthocyanins and juice colour, but also had lowest berry subjected to different water regimens as a result of the and juice TA. The reduction in colour was unexpected, variation of soil water-holding capacity and evaporative since Scott Henry treatments had the least dense canopies demand. Water deficit accelerated sugar accumulation with the lowest percentage of shaded clusters. In a follow- and malic acid reduction in the juice. Early water defi- up study, Reynolds et al. (1996c) found that wine TA and cits during the growth period had beneficial effects on the pH were reduced and anthocyanins were increased by concentration of anthocyanins and total phenolics in berry Scott Henry training, in both British Columbia and Or- skins. A similar pattern was observed for the phenolic con- egon. Means of five vintages from both wine regions in- centration of wines as well. Limited water availability also dicated that clove, bell pepper and grassy aromas were seemed to increase glycoconjugates in the main aromatic lower in Scott Henry canopy treatments. Cherry and anise components of grapes. Wines produced from grapes of aromas were also higher in Scott Henry wines, but many stressed vineyards were also preferred in tasting trials. flavours, colours and finishes were not increased by verti- Chaves et al. (2007) assessed three irrigation strategies cal canopy division. (deficit irrigation, partial root drying [PRD], fully irrigated) Peterlunger et al. (2002) examined the effect of four train- on two grapevine cultivars (Moscatel and Castelao) in ing systems for Pinot Noir in the Friuli Hills (northeastern Portugal. They indicated that the amount of water could Italy). Simple Guyot, double Guyot, horizontal spurred be decreased by 50% (as in the case of PRD) without cordon and vertical spurred cordon were assessed. As has compromise to fruit composition. Non-irrigated and PRD often been the case with variations to non-divided sys- vines exhibited higher concentrations of berry skin antho- tems, the training systems affected yield but showed little cyanins and total phenols than those in deficit-irrigated or no impact on grape and wine composition, including and fully irrigated vines. These effects on potential qual- grape and wine phenolics. Sensory analysis could not ity were mediated by a reduction in vigour, leading to an show relevant differences among training systems. increase on light interception in the cluster zone. Because plant water status on most dates during the season was Among work with French–American hybrids, horizon- not different between PRD and deficit-irrigated (when dif- tally divided canopies such as GDC and Y-trellises were ferent, PRD even exhibited a higher leaf water potential tested by Reynolds et al. (1995c, 2004a) on Chancellor than deficit-irrigated vines), the authors concluded that grapevines in British Columbia. Yields of divided cano- the growth inhibition in PRD was not a result of dimin- pies (GDC and Y) averaged 42% higher than non-divided ished water status. systems, but cluster weights and berries per cluster tended Anthocyanin biosynthesis is strongly up-regulated in rip- to be lower in the divided canopies. Crop loads (ratio of ening fruit of grapevines grown under drought conditions. yield: weight of cane prunings) of divided canopies ex- Castellarin et al. (2007) investigated the effects of long- ceeded the currently accepted level (10 to 12) beyond term water deficit on the expression of genes coding for which wine quality could be compromised. The GDC sys- flavonoid and anthocyanin biosynthetic enzymes and re- tem produced fruit with the lowest %SS, but also with the lated transcription factors, genes sensitive to endogenous lowest TA and pH and the highest anthocyanin concentra- (sugars, abscisic acid) and environmental (light) stimuli tion. Increased vine spacing led to smaller vine size (per connected to drought stress, and genes developmentally m row), lower cane weights and occasionally lower %SS. regulated in ripening berries. Total anthocyanin concen- Chancellor GDC wines had highest berry flavour. tration increased at harvest in water-stressed fruits by 37 7.5 Irrigation to 57% in two consecutive years. At least 84% of the to- The positive effects of limited irrigation (i.e., regulated tal variation in anthocyanin concentration was explained deficit irrigation) on phenolic analytes may invariably be by a linear relationship between the integral of mRNA a consequence of reduced vine vigour and improved fruit accumulation of the specific anthocyanin biosynthetic gene, UDP-glucose: flavonoid 3-O-glucosyltransferase exposure. Generally, improvements in fruit exposure oc- and metabolite concentration during a time series from cur in situations where mild water deficits have been im- veraison through ripening. Chalcone synthase and flava- posed (Balint and Reynolds 2010). none-3-hydroxylase (F3H) genes of the flavonoid pathway The influence of irrigation on grape and wine composi- showed high correlation as well. Genes coding for flavo- tion was investigated for Agiorgitiko in the Nemea appella- noid 3’,5’-hydroxylase and O-methyltransferase were also tion area in southern Greece by Koundouras et al. (2006). up-regulated in berries from dehydrated plants in which Three non-irrigated plots were studied during vintages that anthocyanin composition was enriched in more hydroxyl- were very hot and devoid of summer rainfall. Vines were ated and more methoxylated derivatives such as malvidin – 31 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY and peonidin. The induction in water-stressed plants of Increases in cluster weight and yield per vine were found structural and regulatory genes of the flavonoid pathway in ABA-treated vines of Cabernet Sauvignon in Mendoza, suggested that interrelationships between developmental Argentina (Quiroga et al. 2009). Vines were subjected to and environmental signalling pathways were magnified weekly ABA applications, from budburst through harvest. by water deficits, which actively promoted fruit matura- They concluded that yield increased due to increased ber- tion and, in this context, anthocyanin biosynthesis. It is ry set or reduced early berry abortion brought about by also worthy of note that Downey et al. (2004) likewise ABA. Others (Giribaldi et al. 2009) have shown that ABA found an up-regulation of UDP-glucose flavonoid-3-O- treatment is most effective in enhancing ripening when it glucosyl transferase in exposed fruit post-veraison, and an is applied pre-veraison and not later (50% or more berry enhancement in the activity of a gene encoding flavonol colouration). ABA was more effective than ethephon at synthase in exposed fruit. improving the colour of Crimson Seedless table grapes (Cantin et al. 2007). The ABA treatments were not accom- 8. Exogenous Abscisic Acid Applications panied by any premature berry abscission, as was expected. Crimson Seedless table grapes treated with 300 µL/L Abscisic acid (ABA) is a hormone that plays a major role ABA had their harvest date advanced by 10 to 30 days in plant adaptation to abiotic environmental stresses compared with non-treated vines (Cantin et al. 2007). Ex- (drought, cold and salinity), growth control, seed develop- ogenous applications of ABA increased the anthocyanin ment and germination. ABA is involved in the signalling concentration in skins of the table grape cultivar Redglobe chain of water stress in plants (Antolin et al. 2008, and (Peppi et al. 2007). However, no linear relationship was Jiang and Hartung 2008). ABA also has a major role in found between grape colour variables and anthocyanins, the fruit maturation process in grapes (Hale and Coombe although grapes with high skin anthocyanins appeared 1974), where it is associated with the main molecular pro- darker and more red-coloured than grapes with low an- cesses (Jeong et al. 2004). Transcripts and proteins linked thocyanin concentration (Peppi et al. 2007). Exogenous to ABA biosynthesis have been found in berries during ABA applied to Cabernet Sauvignon clusters led to rapid the maturation process (Castellarin et al. 2007). ABA has accumulation of anthocyanins and flavonols, as well as been described as a mediator, which at certain concentra- enhanced gene activity of the phenylpropanoid and fla- tions, stimulates the expression of genes encoding inver- vonoid pathways (Koyama et al. 2010). In the San Joaquin tase or controlling phenol and anthocyanin biosynthesis Valley in California, Gu et al. (2011) applied ABA to either (Gagné et al. 2006, Gambetta et al. 2010, and Koyama clusters or leaves of Cabernet Sauvignon and found that et al. 2010). Exogenous ABA treatments at veraison have berry anthocyanins increased only when ABA was applied enhanced several processes involved in grape berry matu- to the clusters. From the winemaking point of view, an- ration, such as the accumulation of %SS, the decrease in thocyanin composition affects colour stability. Cyanidin, the concentration of organic acids and the accumulation delphinidin and petunidin have ortho-diphenolic groups of anthocyanin (Coombe and Hale 1973, Gambetta et al. that enhance susceptibility to oxidation, while methox- 2010, and Yamane et al. 2006). ylated anthocyanins such as peonidin and malvidin are more stable. ABA is synthesized in roots and leaves, and transported to grape clusters via the phloem (Shiozaki et al. 1999). In the Niagara Peninsula, Balint and Reynolds (2013) con- Grape berry ABA concentration increases just before ve- ducted two experiments in a Cabernet Sauvignon block. raison (Hale and Coombe 1974). Besides its genetic con- Both experimental years (2008, 2009) were characterized trol, ABA concentration and its effects are moderated by by higher rainfall and lower temperatures than average. environmental conditions such as temperature (Koshita et The first experiment initiated one week pre-veraison con- al. 2007), light (Jeong et al. 2004) and water stress (An- sisted of four treatments (untreated control, 300 mg ABA/L tolín et al. 2008). Increased concentrations of ABA during applied to the full canopy, clusters only, leaves only) ap- the growing season are associated with growth restriction plied three times at two-week intervals. The second experi- resulting from water stress, which is postulated to be an ment had three treatments (0 [control] 150, 300 mg ABA/L adaptation mechanism to the adverse conditions imposed applied to clusters only). In both years, the control still had by water stress (Jiang and Hartung 2008). In Vitis vinif- clusters with 20% green berries two to four weeks after era, periods of moderate water deficit (predawn leaf wa- experiment initiation. Following treatment, berries had a ter potential of ≈ -0.8 MPa) during ripening enhanced the lower ABA uptake rate than leaves. Both ABA rates has- polyphenol and anthocyanin concentrations in the berries tened the onset of veraison. In both years the transpiration (Matthews and Anderson 1988). rate, leaf ψ and fruit composition were most affected in the – 32 – Impact of Vineyard Management on Grape Maturity leaves-only and whole canopy treatments. At harvest, Brix A failure to find good agreement between analytical and was higher and the berry weight was lower in the ABA sensory results may be due to variability among judges, treatments than in the control. Total anthocyanins and to- but may also be ascribed in part to the confounding taster tal phenols also increased in most ABA treatments. Berries response to non-floral monoterpenes such as -terpineol. from clusters treated with the highest ABA rate showed a This underscores the need to follow up work of this na- higher red-blue colour intensity and also had highest an- ture with gas chromatographic analyses of wines, to over- thocyanins and phenols compared to berries from other come problems of this nature. Our work and that of others treatments. The treated vines showed enhancement in in- have demonstrated that not only do vineyard and cellar dividual anthocyanins and acetylated anthocyanins, with practices often affect aroma compound concentration in significant changes in the ratios of cyanidin, petunidin and berries and juices, but very often organoleptic evaluation malvidin occurring among the treatments. Exogenous ABA may confirm these analytical results. Our specific conclu- was effective in accelerating onset of veraison and improv- sions to date are (1) PVT are more responsive to viticul- ing the grape composition of Cabernet Sauvignon. tural and oenological practices than FVT; (2) FVT and PVT Exogenous ABA (or products with similar effects) could are rarely correlated with %SS, TA or pH, thus cannot be provide considerable benefits to the wine industry in terms predicted by standard harvest indices; (3) losses in FVT of grape composition, wine style and winery scheduling, and PVT can occur between the berry and juice stages, particularly in wet and cool years. It would be necessary hence the desirability of skin contact; and (4) FVT and to understand and assess the long-term effects of using PVT concentrations can, in some cases, be related to wine exogenous ABA not only on general vine metabolism and tasting results. physiology, but also on wine organoleptic characteristics. It is still not clear if ABA acts alone or in combination Acknowledgement with other hormones on different processes during the ripening period. However, ABA could be successfully in- The author would like to acknowledge the contribution of troduced as an alternative cultural practice, particularly in Gabriel Balint to this paper. cool years, and also in regions and growing seasons when there is a high chance of early frost to occur, and a con- References comitant potential of premature loss of foliage. The temporal advancement of ripening through hormonal control Abbott, N. A., P. J. Williams, and B. G. Coombe. 1993. might be an asset because earlier fruit maturation is a dis- Measure of potential wine quality by analysis of grape tinct advantage in cooler areas or areas with a high risk glycosides. Proceedings of the Eighth Australian Wine of early frost occurrence, and where an early end of the Industry Technical Conference. Stockley, C. S., R.S. John- growing season might prevent adequate fruit maturation. stone, et al. (Eds.). Winetitles, Adelaide, SA. 72-75.

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Arnold, R. A., and A. M. Bledsoe. 1990. The effect of Bergqvist, J., N. Dokoozlian, and N. Ebisuda. 2001. Sun- various leaf removal treatments on the aroma and flavor light exposure and temperature effects on berry growth of Sauvignon blanc wine. Amer. J. Enol. Vitic. 41:74-76. and composition of Cabernet Sauvignon and Grenache in the central San Joaquin Valley of California. Amer. J. Augustyn, O. P. H., A. Rapp, and J. Wyk. 1982. Some Enol. Vitic. 52:1-7. volatile aroma components of Vitis vinifera L. cv. Sauvi- gnon blanc. S. Afr. J.Enol. Vitic. 3:53-60. Bindon, K. A., P. R. Dry, and B. R. Loveys. 2007. Influ- ence of plant water status on the production of C-13-nor- Austerweil, G. l946. Quelques observations sur les par- isoprenoid precursors in Vitis vinifera L. cv. Cabernet fums des vins. Ind. Parfum. 1:195-199. Sauvignon grape berries. J. Agric. Food Chem. 55:4493- Balint, G., and A. G. Reynolds. 2010. Effect of different 4500. irrigation strategies on vine physiology and grape quality Blanchard, L., P. Darriet, and D. Dubourdieu. 2004. of Cabernet Sauvignon and Sauvignon blanc in a cool- Reactivity of 3-mercaptohexanol in red wine: Impact of climate area. Progrès Agricole et Viticole. 127(11):232- oxygen, phenolic fraction and sulfur dioxide. Amer. J. 41. Enol. Vitic. 55:115-120.

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McCarthy, M. G., R. M. Cirami, and D. G. Furkaliev. Peyrot des Gachons, C, T. Tominaga, and D. Dubourdieu. 1987. Effect of crop load and vegetative growth control 2000. Measuring the aromatic potential of Vitis vinifera on wine quality. Proceedings of the 6th Australian Wine L. cv. Sauvignon blanc grapes by assaying S-cysteine Industry Technical Conference. Lee, T. (ed.), Australian conjugates, precursors of the volatile thiols responsible Industrial Publishers, Adelaide, S. Australia. 75-77. for their varietal aroma. J. Agric. Food Chem. 48:3387- McCarthy, M. G., and B. G. Coombe. 1985. Water status 3391. and winegrape quality. Acta Hortic. 171:447-456. Peyrot des Gachons, C., C. Van Leeuwen, T. Tominaga, Murat, M. L., T. Tominaga, and D. Dubourdieu. 2001a. J. P. Soyer, J. P. Gaudillère, and D. Dubourdieu. 2005. Assessing the aromatic potential of Cabernet Sauvignon Influence of water and nitrogen deficit on fruit ripen- and Merlot musts used to produce rosé wine by assaying ing and aroma potential of Vitis vinifera L cv Sauvignon the cysteinylated precursor of 3-mercaptohexan-1-ol. J. blanc in field conditions. J. Sci Food Agric. 85:73-85. Agric. Food Chem. 49:5412-5417. Pickering, G. J., J. Lin, A. G. Reynolds, G. Soleas, and Murat, M. L., I. Masneuf, P. Darriet, V. Lavigne, T. Tom- R. Riesen. 2006. The evaluation of remedial treatments inga, and D. Dubourdieu. 2001b. Effect of Saccharomy- for wine affected by Harmonia axyridis. Int. J. Food Sci. ces cerevisiae yeast strains on the liberation of volatile Technol. 41:77-86. thiols in Sauvignon blanc wine. Amer. J. Enol. Vitic. Pickering, G. J., J. Lin, R. Riesen, A. G. Reynolds, I. 52:136-139. Brindle, and G. Soleas. 2004. Influence of Harmonia Noble, A. C. 1979. Evaluation of Chardonnay wines ob- axyridis on the sensory properties of white and red wine. tained from sites with different soil compositions. Amer. Amer. J. Enol. Vitic. 55:153-159. J. Enol. Vitic, 30:214-217. Quiroga, A. M., F. J. Berli, D. Moreno, J. B. Cavagnaro, Oliveira, C., A. C. Ferreira, P. Costa, J. Guerra, and P. G. and R. Bottini. 2009. Abscisic acid sprays significantly de Pinho. 2004. Effect of some viticultural parameters on increase yield per plant in vineyard-grown wine grape the grape carotenoid profile. J. Agric. and Food Chem. (Vitis vinifera L.) cv. Cabernet Sauvignon through in- 52:4178-4184. creased berry set with no negative effects on anthocyanin – 38 – Impact of Vineyard Management on Grape Maturity content and total polyphenol index of both juice. J. Plant Reynolds, A. G., and D. A. Wardle. 1989a. Impact of Growth Reg. 80:28-35. several canopy manipulation practices on growth, yield, fruit composition, and wine quality of Gewürztraminer. Razungles, A. J., R. L. Baumes, C. Dufour, C. N. Sznaper, Amer. J. Enol. Vitic. 40:121-129. C. L. Bayonove. 1998. Effect of sun exposure on carotenoids and C-13-norisoprenoid glycosides in Syrah Reynolds, A. G., and D. A. Wardle. 1989b. Influence of berries (Vitis vinifera L.). Sciences Des Aliments. 18:361- fruit microclimate on monoterpene levels of Gewürztra- 373. miner. Amer. J. Enol. Vitic. 40:149-154.

Reynolds, A. G., C. G. Edwards, D. A. Wardle, D. R. Reynolds, A. G., and D. A. Wardle. 1989c. Effects of Webster, and M. J. Dever. 1994a. Shoot density affects timing and severity of summer hedging on growth, yield, Riesling grapevines. I. Vine performance. J. Amer. Soc. fruit composition, and canopy characteristics of De Hort. Sci. 119:874-880. Chaunac. II. Yield and fruit composition. Amer. J. Enol. Vitic. 40:299-308. Reynolds, A. G., C. G. Edwards, D. A. Wardle, D. R. Webster, and M. J. Dever. 1994b. Shoot density affects Reynolds, A. G., D. A. Wardle, M. A. Cliff, and M. J. Riesling grapevines. II. Wine composition and sensory King. 2004a. Impact of training system and vine spac- response. J. Amer. Soc. Hort. Sci. 119:880-892. ing on vine performance, berry composition, and wine sensory attributes of Seyval and Chancellor. Amer. J. Enol. Reynolds, A. G., T. Molek, and C. de Savigny. 2005. Vitic. 55:84-95. Timing of shoot thinning in Vitis vinifera: Impacts on yield and fruit composition variables. Amer. J. Enol. Vitic. Reynolds, A. G., D. A. Wardle, and M. J. Dever. 1993. 56:343-356. Terpenes in berries and juices of Vitis vinifera in response to pressing, harvest date, and skin contact. HortScience. Reynolds, A. G., P. Parchomchuk, R. Berard, A. P. Naylor, 28:920-924. and E. J. Hogue. 2006. Gewürztraminer vines respond to length of water stress duration. Int. J. Fruit Sci. 5(4):75-94. Reynolds, A. G., D. A. Wardle, and M. J. Dever. 1994d Shoot density effects on Riesling grapevines: interaction Reynolds, A. G., R. M. Pool, and L. R. Mattick. 1986. with cordon age. Amer. J. Enol. Vitic. 45:435-443. Influence of cluster exposure on fruit composition and wine quality of Seyval blanc. Vitis. 25:85-95. Reynolds, A. G., D. A. Wardle, and M. J. Dever. 1996a. Vine performance, fruit composition, and wine sensory Reynolds, A. G., S. F. Price, D. A. Wardle, and B. T. attributes of Gewürztraminer in response to vineyard Watson. 1994c. Fruit environment and crop level effects location and canopy manipulation. Amer. J. Enol. Vitic. on Pinot noir. I. Vine performance and fruit composition. 47:77-92. Amer. J. Enol. Vitic. 45:452-459. Reynolds, A. G., D. A. Wardle, J. W. Hall, and M. J. De- Reynolds, A. G., J. W. Schlosser, R. Power, R. Roberts, ver. 1995a. Fruit maturation in four Vitis vinifera cultivars and C. de Savigny. 2007a. Magnitude and interaction of in response to vineyard location and basal leaf removal. viticultural and enological of effects. I. Impact of canopy Amer. J. Enol. Vitic. 46:542-558. management and yeast strain on sensory and chemical composition of Chardonnay musqué. Amer. J. Enol. Vitic. Reynolds, A. G., D. A. Wardle, and A. P. Naylor. 1995c. 58:12-24. Impact of training system and vine spacing on vine performance and berry composition of Chancellor. Amer. J. Reynolds, A. G., J. W. Schlosser, D. Sorokowsky, R. Rob- Enol. Vitic. 46:88-97. erts, and C. de Savigny. 2007b. Magnitude and interaction of viticultural and enological of effects. II. Relative Reynolds, A. G., D. A. Wardle, and A. P. Naylor. 1996b. impacts of cluster thinning and yeast strain on composi- Impact of training system, vine spacing, and basal leaf tion and sensory attributes of Chardonnay musqué. Amer. removal on Riesling. Vine performance, berry composi- J. Enol. Vitic. 58:25-41. tion, canopy microclimate, and vineyard labor requirements. Amer. J. Enol. Vitic. 47:63-76. Reynolds, A. G., I. Senchuk, and C. de Savigny. 2007c. Use of GPS and GIS for elucidation of the basis for ter- Reynolds, A.G., S. Yerle, B. T. Watson, S. F. Price, and roir. Spatial variation in an Ontario Riesling vineyard. D. A. Wardle. 1996c. Fruit environment and crop level Amer. J. Enol. Vitic. 58:145-162. effects on Pinot noir. III. Composition and descriptive – 39 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY analysis of Oregon and British Columbia wines. Amer. J. Smart, R. E. 1982. Vine manipulation to improve wine Enol. Vitic. 47:329-39. grape quality. Proceedings of the University of Califor- nia, Davis, Grape and Wine Centennial Symposium. Ribéreau-Gayon, P., J. N. Boidron, and A. Terrier. 1975. Webb AD (Ed.), University of California Press, Berkeley. Aroma of muscat grape varieties. J. Agric. Food Chem. 362‑375. 23:1042-1047. Smart, R. E., J. B. Robinson, G. Due, and C. J. Brien. Ristic, R., M. O. Downey, P. G. Iland, K. Bindon, I. L. 1985b. Canopy microclimate modification for the cul- Francis, M. Herderich, S. P. Robinson. 2007. Exclusion tivar Shiraz. II. Effects on must and wine composition. of sunlight from Shiraz grapes alters wine colour, tan- Vitis. 24:119‑128. nin and sensory properties. Austral. J. Grape and Wine Research. 13:53-65. Smith, S., I. C. Codrington, M. Robertson, and R. E. Smart RE. 1988. Viticultural and oenological implications Rodopoulo, A. K., I. A. Egorov, A. A. Bezzubov, and K. of leaf removal for New Zealand vineyards. Proceedings P. Skuin. 1974. [Compounds responsible for the aroma of the 2nd International Symposium Cool Climate Vitic. of grapes and their role in formation of the bouquet of Oenol., 11-15 January, 1988, Auckland, New Zealand. wine]. Russian. Prikl. Biokhim. Mikrobiol. 10:280-287. Smart, R. E., R. J. Thornton, S. B. Rodriguez, and J. E. Roujou de Boubée, D., A. M. Cumsille, M. Pons, and Young JE (eds.), New Zealand Society for Viticulture and D. Dubourdieu. 2002. Location of 2-methoxy-3-isobu- Oenology, Auckland. 127-133. tylpyrazine in Cabernet Sauvignon grape bunches and Spayd, S. E., J. M. Tarara, D. L. Mee, J. C. Ferguson. its extractability during vinification. Amer. J. Enol. Vitic. 2002. Separation of sunlight and temperature effects on 53:1–5. the composition of Vitis vinifera cv. Merlot berries. Amer. Roujou de Boubée, D., C. Van Leeuwen, and D. Dubor- J. Enol. Vitic. 53:171-182. dieu. 2000. Organoleptic impact of 2-methoxy-3-isobu- Stevens, K. L., J. Bomben, A. Lee, and W. H. McFadden. tylpyrazine on red Bordeaux and Loire wines. Effect of 1966. Volatiles from grapes. Muscat of Alexandria. J. environmental conditions on concentrations in grapes Agric. Food Chem. 14:249-252. during ripening. J Agric Food Chem. 48:4830–4834. Strauss, C.R., B. Wilson, P. R. Gooley, and P. J. Williams. Sala, C., O. Busto, J. Guasch, and F. Zamora. 2004. 1986. Role of monoterpenes in grape and wine flavor. Influence of vine training and sunlight exposure on the Amer. Chem. Soc. Symp. 317:222-242. 3-alkyl-2-methoxypyrazines content in musts and wines from the Vitis vinifera variety Cabernet Sauvignon. J. Terrier, A., J.-N. Boidron, and P. Ribéreau-Gayon. 1972a. Agric. Food Chem. 52:3492-3497. L’identification des composés terpéniques dans les raisins de V. vinifera. C.R. Acad Sci. Ser. D. 275:495-497. Sala, C., O. Busto, J. Guasch, and F. Zamora. 2005. Con- tents of 3-alkyl-2-methoxypyrazines in musts and wines Terrier, A., J.-N. Boidron, and P. Ribéreau-Gayon. 1972b from Vitis vinifera variety Cabernet Sauvignon: influence Teneurs en composés terpéniques des raisins de Vitis of irrigation and plantation density. J. Sci. Food Agric. vinifera. C.R. Acad. Sci. Ser. D. 275:941-944. 85:1131-1136. Tominaga, T., R. Baltenweck-Guyot, C. Peyrot des Sala, C., M. Mestres, M. P. Marti, O. Busto, and J. Gachons, and D. Dubourdieu. 2000. Contribution of Guasch. 2000. Headspace solid-phase microextraction volatile thiols to the aromas of white wine made from method for determining 3-alkyl-2-methoxypyrazines in several Vitis vinifera grape varieties. Amer. J. Enol. Vitic. musts by means of polydimethylsiloxane-divinylbenzene 51:178-181. fibres. J Chromatogr A. 880:93–99. Tominaga, T., A. Furrer, R. Henry, and D. Dubourdieu. Schreier, P., F. Drawert, and A. Junker A. 1976. Identifica- 1998a. Identification of new volatile thiols in the aroma tion of volatile constituents from grapes. J. Agric. Food of Vitis vinifera L. var. Sauvignon blanc wines. Flavour Chem. 24:331-336. Fragrance J. 13:159-162.

Shiozaki, S., Y. Kamata, T. Ogata, S. Horiuchi, and K. Ka- Tominaga, T., C. Peyrots des Gachons, and D. Dubour- wase. 1999. Localisation of abscisic acid in grape berry dieu. 1998b. A new type of flavor precursors in Vitis by immunohistochemical techniques. J. Japan. Soc. Hort. vinifera L. cv. Sauvignon blanc: S-cysteine conjugates. J. Sci. 68:1-9. Agric. Food Chem. 46:5215-5219. – 40 – Impact of Vineyard Management on Grape Maturity

Van Wyck, C. J., A. D. Webb, and R. E. Kepner. 1967. training systems on Viognier grape and wine composi- Some volatile constituents of Vitis vinifera variety White tion. Amer. J. Enol. Vitic. 59:11-21. Riesling. I Grape juice. J. Food Sci. 32:660-664.

Weaver, R. J., S. B. McCune, and M. A. Amerine. 1961. List of Figures Effect of level of crop on vine behavior and wine compo- 1. Effects of cluster exposure on monoterpene composi- sition in Carignane and Grenache grapes. Amer. J. Enol. tion of Gewurztraminer, Kaleden, British Columbia, 1986: Vitic. 12:175-184. A: Free volatile terpenes (mg/L); B: Potentially volatile terpenes (mg/L). *,**,***, ns: Significant at p < 0.05, 0.01, Webb, A. D. and R. E. Kepner. 1957. Some volatile 0.001, or not significant, respectively. Redrawn from aroma constituents of Vitis vinifera var. Muscat of Alexan- Reynolds and Wardle (1989b). dria. Food Res. 22:384-394. 2. Impact of six thinning times on Chardonnay musqué Webb, A. D., R. E. Kepner, and L. Maggiora. 1966. Gas berry potentially volatile terpene concentration 1999 to chromatographic comparison of volatile aroma materials 2001. Asterisks indicate significant difference from the extracted from eight different muscat flavored varieties of control, p < 0.05, Dunnett’s t-test. From Reynolds et al. Vitis vinifera. Amer. J. Enol. Vitic. 17:247-254. (2007b).

Webster, D., C. G. Edwards, S. E. Spayd, J. C. Peterson, 3. Potentially volatile terpene concentration of Riesling and B. J. Seymour. 1993. Influence of nitrogen fertiliza- berries subjected to five trellising treatments, 1988 to tion on the concentrations of monoterpenes, higher 1992. Bars within years containing different letters are sig- alcohols, and esters in aged White Riesling wines. Amer. nificantly different at p < 0.05, Duncan’s multiple range J. Enol. Vitic. 44:275-84. test. Figure was redrawn from Reynolds et al. (1996).

Winkler, A. J., J. A. Cook, W. M. Kliewer, and L. A. Lider. 4. Effect of three irrigation deficit times on free volatile 1974. General Viticulture. Univ. of Calif. Press, Berkeley, terpene (FVT) and potentially volatile terpene (PVT) con- Los Angeles, and London. centration of Gewürztraminer berries, sampled at veraison and harvest, 1995. Legend: postbloom, lag phase, and Wolf, T. K., R. M. Pool, and L. R. Mattick. 1986. Respons- veraison-imposed deficits respectively; ***, ns: significant es of young Chardonnay grapevines to shoot tipping, at p < 0.001 or not significant, respectively; L, Q: linear ethephon, and basal leaf removal. Amer. J. Enol. Vitic. or quadratic trends respectively. Data are pooled across 37:263-268. three vineyard floor management treatments. Figure was Yamakawa, T., S. Kato, K. Ishida, T. Kodama, and Y. Mi- redrawn from Reynolds et al. (2006). noda. 1983. Production of anthocyanins by Vitis cells in 5. GIS-derived maps of the Riesling block on the Paul Bosc suspension culture. Agric. Biol. Chem. 47:2185-2191. Estate, St. Davids, ON, 2005 to 2007. A to C: Leaf water Yamane, T., S. T. Jeong, N. Goto-Yamamoto, Y. Koshita, potential, 2005, 2006 and 2007 respectively; D to F: Po- tentially volatile terpenes (PVT), 2005, 2006 and 2007 and S. Kobayashi. 2006. Effects of temperature on antho- respectively. Note how (a) spatial variation in both leaf cyanin biosynthesis in grape berry skins. Amer. J. Enol. water potential and PVT are temporally stable across the Vitic. 57:54-59. three seasons; (b) the patterns of leaf water potential and Zoecklein, B. W., T. K. Wolf, J. E. Marcy, and Y. Jasinski. PVT are very similar spatially. These observations suggest 1998a. Effect of fruit zone leaf thinning on glycosides that high flavour zones in vineyards are temporally stable and selected aglycone concentrations of Riesling (Vitis and are related to vine water status. Maps are courtesy of vinifera L.) grapes. Amer. J. Enol. Vitic. 49:35-43. Dr. Jim Willwerth.

Zoecklein, B. W., T. K. Wolf, S. E. Duncan, J. E. Marcy, and Y. Jasinski. 1998b. Effect of fruit zone leaf removal on total glucoconjugates and conjugate fraction concentrations of Riesling and Chardonnay (Vitis vinifera L.) grapes. Amer. J. Enol. Vitic. 49:259-265.

Zoecklein, B. W., T. K. Wolf, L. Pélanne, M. K. Miller, and S. S. Birkenmaier. 2008. Effect of vertical shoot- positioned, Smart-Dyson, and Geneva double-curtain – 41 –

PRECISION IRRIGATION OF GRAPEVINES: METHODS, TOOLS AND STRATEGIES TO MAXIMIZE THE QUALITY AND YIELD OF THE HARVEST AND ENSURE WATER SAVINGS

Hernán OJEDA, and Nicolas SAURIN

UE 999, Unité Expérimentale de Pech Rouge, 11430 Gruissan, France

Abstract the total vineyard area. In Argentina, the entire winegrowing area is irrigated (205,000 ha). Vineyard irrigation has been used for a very long time in the so-called “new world vineyards” and is widely prac- In the south of France, vine irrigation has been a reality ticed. Its adoption in the French Mediterranean regions since the early 2000s. Languedoc-Roussillon is the main is much more recent and it is one of the first techniques irrigated area in France, with 26,000 ha (11% of the vine- adopted by the grapegrowers to combat the impact of cli- yard area), followed by the Provence-Alpes-Côte d’Azur mate change. Vineyard irrigation is a tool that makes it (PACA) administrative region with 10,000 ha of irrigated possible to maintain both the quality and the quantity of vines.1 This area is increasing due to climate change and the harvest. Irrigation control is based on the characteriza- the current grapegrowing and winemaking crisis, which tion of vine water status and on the knowledge of plant requires an evolutionary adaptation of agricultural tech- response to water deficits according to the phenological niques for Mediterranean vineyards. In fact, the rise in stage. This knowledge helps define an irrigation strategy average temperatures, along with the accompanying sig- adapted to the vineyard objective, e.g., grape juice, white nificant increase in evapotranspiration, generates drought wines, red wines or wines for aging. during the growing cycle, induced by a severe and early water deficit (figure 1). 1. Vines and Water Winegrowers in the region are increasingly confronted Around the world, grapevines are grown in areas where with the choice of accepting the consequences of severe the water regime is highly variable according to the cli- water stress or irrigating to prevent the serious degradation mate (e.g., rainfall and evapotranspiration) and the type of of yields and crop quality. This has led the Languedoc- soil (the water-holding capacity). In several wine-produc- Roussillon region to carry out the Aqua Domitia project, ing regions of countries such as Australia, Argentina, the co-financed mainly by the regional government in col- United States (California) and Chile, irrigation is a cultiva- laboration with the General Council of the Aude, which tion technique like any other, increasingly used to man- aims to expand the regional hydraulic network by linking age the performance and quality of the grapes and wines. In all these “New World Wine” countries, the irrigated 1 Source: Association des Irrigants des Régions Méditerranéennes vineyard area is now 580,000 hectares, or about 83% of Françaises (AIRMF) – 43 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

600 1000 A 550 900 500 800 450 April-September rains 700 400 April-September ETP 350 600 (mm) Average ETP 1990-2014 300 500 250 400

Rains 200

300 ETP (mm) 150 100 200 50 100 0 0 350 B 300 250 Unfavourable water balance 200 150 100

mm 50 0 -50 -100 -150 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 9 9 9 9 9 9 9 9 9 9 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9 9 9 9 9 9 9 9 9 9 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 Year

Figure 1. A: Rains and evapotranspiration (ETP) fluctuations; B: Dryness Index (DI) Source: Tonietto and Carbonneau 2004, INRA, Unité Expérimentale de Pech Rouge, Gruissan, France

Ȇ ȇ

Absence of water deficit • “excessive” notion Drains, •ȆȆberry size and vigor Cover crops, etc. • qualitative components dilution • negative effects (ȇquality and Ȇ yields) Natural factors Vineyard - Climate Moderate water deficit water status - Vintage - Soil • “moderate” “controlled” notion • ȇberry size and vigor • ȆȆsynthesis and concentration of quality components Irrigation, etc. • positive effects (Ȇquality and Ǟyields)

Water stress How irrigating? • “excessive” notion • Physiological dysfunction • detrimental eﬀects (cavitation, thyllose, folletage, ﬂa, etc. (ȇquality and ȇyields)

Figure 2. Different situations and possible consequences of vineyard water status according to the natural characteristics of the terroirs – 44 – Precision Irrigation of Grapevines waterways fed by the Rhône with those fed by the Orb, flooding (figure 3). This limited the development of ir- Hérault and Aude Rivers.2 rigation to those areas where it was possible to system- atically distribute water, adequately prepare the site and In this context, responsible irrigation management should have a significant quantity of water available, notably be based on the quantitative analysis of the need for water due to large losses of water through leaching (over 50%). that takes into account the soil and climate characteristics The incorporation of localized drip irrigation systems of the plots and the irrigation strategies (the demand) in has intensified in the winegrowing world since the early relation to the production target, with the possible water 1990s, mainly due to the system’s ability to save water resources (the state of resources) and, in the longer term, and the precision of its management. At present, local- to consider the evolution of this balance in a changing ized drip irrigation is the most common irrigation meth- climate (figure 2). od in the world. Therefore, controlling irrigation to regulate the production When well-managed, drip irrigation technology allows of a quality harvest has become a constant concern of the better control of the vineyard water status and ensures winemaking professionals who demand more reliable and good water management with preciseness, labour-saving powerful tools to assist decision-making to manage the automation and water savings. It is also possible to prac- water status of the vines. tice fertigation, i.e., the application of nutrients through irrigation. However, in some soils, the salinity of the root 2. Irrigation Methods bulb must be constantly monitored. Furthermore, in some Throughout the winegrowing world, the method of ir- sandy soils prolonged irrigation system breakdown can rigation traditionally used for viticulture was gravity or cause the soil in contact with the root to dry out very rap- idly, with catastrophic results for the vine. 2 http://www.reseau-hydraulique-regional.fr/presentation_du_pro- jet-72.html

A B C D

E F G

Figure 3. Different types of irrigation used for viticulture around the world. A: By submersion in pools (Ica, Peru); B: Californian flooding (Mendoza, Argentina); C: By gravity with grooves; D: By gravity with melgas (Mendoza, Argentina); E: Sprinkling (Osoyoos, Canada); F: Microsprinkling (Stellenbosch, South Africa); G: Drip (Mendoza, Argentina).

– 45 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

3. Decision-making Methods Methods not based on direct measurements of the plant: Estimating crop evapotranspiration from climate Several direct and indirect techniques for estimating the data (Sammis et al. 1988, Allen et al. 1989, Pereira et plant water status or water resources available have been al. 1999, and McCarthy 1997); availability of soil water proposed for the vine. In general, they can be classified (McCarthy 1997, Lebon et al. 2003, Peregrino et al. 2004 into two main categories. and 2006, and Loveys et al. 2005); the use of soil mois- Methods based on measurements of the plant: Stomatal ture sensors (tensiometers, electrical resistance, neutron conductance with potometers or gas exchange analyzers probes, probes TDR and FDR, etc.) (Topp et al. 1980, (Bravdo and Naor 1996, Flexas et al. 2002, Cifre et al. Ortega-Farías and Acevedo 2004, and Loveys et al. 2005); or calculation of indices based on one or more methods 2005, and Loveys et al. 2005); leaf water potential with (McCarthy 1997, Colaizzi et al. 2003, and Ortega-Farías the pressure chamber (McCutchan and Shackel 1992, et al. 2004). Schultz 1996, Choné et al. 2001, Carbonneau et al. 2004, Girona et al. 2006, and Sibille et al. 2007); transpiration Among all the possible tools and methods for estimating with sap flow sensors (Yunusa et al. 2000, Fernandez et the plant water status and water resources available for al. 2001, Escalona et al. 2002, Cifre et al. 2005, and Sau- the vine, it is advisable to favour those where the deci- rin et al. 2011); estimate the water potential of the plant sion is based on measures interpreting of the physiologi- with the use of hygrometers on the stem (Dixon and Tyree cal functioning of the plant, because they integrate all the 1984, and Hessdörfer et al. 2013); dendrometry to moni- parameters responsible for the water status of the vineyard tor trunk diameter fluctuations (Loveys et al. 2001, Naor (i.e., evapotranspiration [ETP], rainfall, soil type, vinicul- and Cohen 2003, and Cifre et al. 2005); temperature mea- ture practices, etc.). suring of leaf and canopy (Idso 1982, Sinclair et al. 1984, By far the best method is still the leaf water potential (Car- Jones 1999, and Jones et al. 2002); determination of the bonneau 1998, Choné et al. 2001, Ojeda et al. 2001, Wil- carbon isotopic ratio (13C/12C) on grapes (van Leeuwen liams and Araujo 2002, and Deloire et al. 2004), which et al. 2001, and Gaudillère et al. 2002). was gradually adopted by wine companies as a method

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Canada Italy Germany Italy Chile

Chile Chile

Figure 4. Determining vine water status with the pressure chamber – 46 – Precision Irrigation of Grapevines to support decision-making regarding irrigation (Figure 4). able for other production targets, like concentrated must Leaf water potential, which is determined with a pressure or grape juice. chamber (Scholander et al., 1965), led to the establish- A progressive water deficit during the ripening period is ment of solid reference values, valid worldwide and for different agro-climatic conditions, particularly for pre- conducive to reduced berry size, and therefore reduced dawn leaf water potential values. yield, which tends to concentrate phenolic compounds, predominantly the anthocyanins (Ojeda et al. 2002). This Other techniques may be more relevant in a specific con- is also associated with stimulation of the secondary me- text, more economical or easier to implement. They can tabolism. However, the optimal water status thresholds be useful and precise provided they are close to the refer- are likely to be different when it comes to promoting phe- ence values obtained through the leaf water potential. nols or aroma precursors. As aroma precursors are more susceptible than phenols to high water deficit (Peyrot des 4. Water Status and Its Effect on the Vine Gachons et al. 2005, and Tejerina et al. 2013), it is impor- Irrigation is a major tool for controlling the vineyard wa- tant to avoid high water deficits when the aromas are a ter status according to the characteristics of the particular priority, especially for white wines. plot and to the production goals. For proper management, Vineyard water status during the veraison and harvest pe- the grapegrower must understand how the plant responds riod determines in large part the type of wine produced to water stress according to the different phenological (Deloire et al. 2005). When there is no water deficit at all, stages. herbaceous, diluted and acid wines are produced. In the During the period from budding to flowering, shoot case of very severe water stress, red wines are overly tan- growth is a priority. Vegetative growth is very sensitive to nic, hard, astringent and high alcohol, while whites lose water deficits. Shoot growth decreases or stops at rela- much of their aroma. tively low stress levels, which do not affect such physi- After harvest, it is important that the vine return to an un- ological parameters as photosynthesis and transpiration constrained water status, in order not to disturb the vine’s (Williams et al. 1994). Consequently, during this period the vine must not be affected by a major water deficit if metabolism, which is active during this period. Indeed, shoot growth is to occur normally – leaf area develops the vine, now free of grape bunches, directs photosyn- through an adequate supply of water to the roots. thesis to the areas for reserves, i.e., the roots, trunk and branches (Champagnol 1984), increases the absorption of Between fruit-set and veraison, the water status has a minerals (Conradie 2005) and, in some cases, resumes the strong influence on yield by affecting berry size (Becker production of new roots (Freeman and Smart 1976, and and Zimmermann 1984, McCarthy 1997, and Ojeda et van Zyl 1984). al. 2001). The controlled reduction of berry size can be a quality target knowing that berry size determines the sur- In summary, during the period of grape ripening between face-to-volume ratio and subsequently the dilution of the veraison and harvest, as the water deficit levels rise, the specific constituents of the skin, including phenols and levels of quality-related components (e.g., phenols, aroma aroma precursors, in the volume of must or wine (Sin- precursors, sugars, etc.) also rise, despite the reduction in gleton 1972, Cordonnier 1976, and Ojeda et al. 2002). yield, notably by reducing berry size (figure 5). Neverthe- Nutrient uptake may also be affected if the drought is ma- less, beyond a certain water deficit threshold that can be jor during this period. This can only be done correctly if considered optimal, the grapes produce no more so-called minerals are diluted in a water solution easily available “qualitative” components, while the physiological (i.e., to the roots (Keller 2005), and for a period of maximum photosynthesis, stomatal conductance and transpiration) consumption of nitrogen, potassium, phosphorus and cal- and quantitative (e.g., vegetative growth, yield, etc.) pa- cium that is mostly between fruit-set and veraison (Fregoni rameters continue to decrease. This optimum water deficit 1985). threshold varies according to the desired quality param- The absence of any water deficit during the stage of grape eter, such as phenolic components in red wines or aroma ripening between veraison and harvest generally promotes precursors in white wines. More severe water deficit lev- high yields. Qualitative components, such as polyphenols els strongly reduce all parameters (qualitative, quantita- and sugars, are diluted by the effect of increasing berry tive and physiological) and lead to a serious weakening of size (Ojeda et al. 2002). Therefore, this situation should plants that can cause survival problems for some varietals be avoided for the production of quality wines, but is suit- if the situation persists for several successive vintages. – 47 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

These results justify the interest in expanding research to 5. Irrigation Strategies establish the optimum water status level for each situa- Models for irrigation management in accordance with the tion, varietal, water delivery system and training system/ optimum level of vine water status for each stage in the terroir combination, to obtain the best quality/yield ratio. growing cycle have been proposed (Ojeda 2007, 2008). In parallel, we must continue studying the physiological On this basis, irrigation strategies began to be applied in aspects that explain the adaptation mechanisms of differ- different wine regions of the world, and several compa- ent varietals to the hydric characteristics of different soils nies are starting to offer services and tools to help and in the context of climate change. Important contributions support grape producers in the implementation of these are already available to establish the physiological re- strategies3, 4, 5. We can foresee some different alternatives sponse curves (e.g., photosynthesis, transpiration, stoma- possible for an irrigation strategy based on the vineyard tal conductance, etc.) in relation to different water deficit objective, the growing season and the water deficit level levels (Prieto 2012). (Figure 6).

Units Aroma Thus, for a vineyard oriented toward the production of precursors phenolics grape juice with the aim of high yields per hectare, the Quality parameters Photosytnthesis transpiration irrigation strategy to follow would be to avoid water stress during the entire growing season (Figure 6A) to promote high yields through most of its components. This strate- Qualitative parameters gy is also generally advisable for the production of table wines or for young vineyards.

For a vineyard where the goal is to produce aromatic white No water Water deﬁcit Water wine or fruity red wine, the irrigation should be controlled deﬁcit stress to ensure a slight and gradual water deficit toward the end Grapevine water status

Figure 5. Influence of the water status of the vineyard on 3 http://itkweb.com/solutions/itk-vigne qualitative, quantitative and physiological parameters 4 http://www.fruitionsciences.com/fr/login/irrigation 5 http://www.viverys.com/vivelys-system-vigne.html

Pressure Vegetative period chamber Water potential Herbaceous Ψ b Ψ t Ψ h Shoot growth ripening post-harvest growth of berry 0 0 0 budding ﬂowering- setting veraison harvest leaf fall A -2 -5 -8 B

-4 -8 -11 C D -6 -11 -14 increasing drought -8 -14 -16

Pre-dawn water potential (Ψb), midday stem water potential (Ψt), midday leaf water potential (Ψf),

Figure 6. Possible different irrigation strategies to control the vineyard water status according to the growing season and the type of desired product: A: Concentrated musts, grape juice, table wines and young vineyards in formation B: White wines, light red and fruity wines C: Quality wines, but well equilibrated with a predominance of the fruit to the structure, limit values for white wines D: Quality wines, concentrated, balanced and suitable for aging. – 48 – Precision Irrigation of Grapevines of the veraison–maturity period (Figure 6B) in order not to Carbonneau, A., A. Deloire, and P. Constanza. 2004. Leaf significantly affect berry size and photosynthesis, and to water potential meaning of different modalities of mea- favour the accumulation of sugars, and especially flavour surements. J. Int. Sci. Vigne Vin. 38:15-19. precursors, while controlling vegetative growth. Champagnol, F. 1984. Eléments de physiologie de la vigne For more concentrated wines, one would seek a moderate et de viticulture générale. Montpellier. and progressive water deficit during the ripening period to Choné, X., C. van Leeuwen, D. Dubourdieu, and J. P. facilitate a reduction in berry size, and consequently the Gaudillère. 2001. Stem water potential is a sensitive yield, and to promote the concentration and synthesis of indicator of grapevine water status. Annals of Botany. phenolic compounds, notably anthocyanins (Figure 6C). 97(4):477-483. Another option for red wines is to reach a high water Cifre, J., J. Bota, J. M. Escalona, H. Medrano, and J. Flex- deficit level (Figure 6D), to ensure greater control over as. 2005. Physiological tools for irrigation scheduling in berry size, and a significant increase in the concentration grapevines (Vitis vinifera L.). An open gate to improve of phenols (more colour and structure) despite some re- water-use efficiency? Agriculture, Ecosystems and Envi- duction of aromatic intensity. This strategy is very suitable ronment. 106(2-3):159-170. for red wines for aging but is not recommended for white wines, where the aromatic component is preferred. Colaizzi, P. D., E. M. Barnes, T. R. Clarke, C. Y. Choi, and P. M. Waller. 2003. Estimating soil moisture under low Controlling water in relation to the chosen water status frequency surface irrigation using crop water stress index. model can be very difficult in certain extreme situations. Journal of Irrigation and Drainage Engineering. 129:27-35. In zones with deep soils, clay, high nitrogen content and poor drainage, the strategy must be directed towards the Conradie, W. J. 2005. Partitioning of mineral nutrients and control of excess water retention through soil manage- timing of fertilizer applications for optimum efficiency. ment, using cover crops and canopy management. When Proceedings of the Soil Environment and Vine Mineral the soil is sandy or sandy loam with good drainage, the Nutrition Symposium. P. Christensen and D. R. Smart, risk of water stress is high; therefore, it is necessary to reg- eds. 69-81. American Society for Enology and Viticulture, ularly monitor the water status of the vineyard to prevent Davis, CA. this risk. Cordonnier, R. 1976. Qualité de la vendange et mé- Depending on the strategy, keep the vineyard at appro- thodologie de la sélection viticole. Le Progrès Agricole et priate levels close to the optimum water status level dur- Viticole. 93(24):760-762. ing the entire growing season to ensure maximum ben- Deloire, A., H. Ojeda, O. Zebic, N. Bernard, J.-J. Hunter, efits and to stave off problems caused by excess water or and A. Carbonneau. 2005. Influence of grapevine water drought. (Fig. 6) status on the style of wine. Le Progrès Agricole et Viticole. 122(21):455-462. References Dixon, M. A., and M. T. Tyree. 1984. A new stem hygrom- Allen, R. G., M. E. Jensen, J. L. Wright, and R. D. Burman. eter, corrected for temperature gradients and calibrated 1989. Operational Estimates of Reference Evapotranspira- against the pressure bomb. Plant, Cell and Environment. tion. Agronomy Journal. 81:650-662. 7:693-697.

Becker, N., and H. Zimmermann. 1984. Influence de div- Escalona, J. M., J. Flexas, and H. Medrano. 2002. Drought ers apports d’eau sur des vignes en pots, sur la maturation effects on water flow, photosynthesis and growth of potted des sarments, le développement des baies et la qualité du grapevines. Vitis. 41:57-62. vin. Bull. O. I. V. 573-583. Fernández, J. E., M. J. Palomo, A. Díaz-Espejo, B. E. Cloth- Bravdo, B., and A, Naor. 1996. Effects of water regime on ier, S. R. Green, I. F. Girón, and F. Moreno. 2001. Heat- productivity and quality of fruit and wine. Proceedings of pulse measurements of sap flow in olives for automating the Workshop Strategies to Optimize Wine Grape Quality. irrigation: tests, root flow and diagnostics of water stress. Acta Hort. (ISHS). 427:15-26. Agricultural Water Management. 51:99-123.

Carbonneau, A., 1998. Irrigation, vignoble et produit de Flexas, J., J. Bota, J. M. Escalona, B. Sampol, and H. la vigne. In Traité d’Irrigation. J.-R. Tiercelin, coord. Tec & Medrano. 2002. Effects of drought on photosynthesis in Doc.Lavoisier. Paris. 257-298. grapevines under field conditions: an evaluation of stoma- – 49 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY tal and mesophyll limitations. Funct. Plant Biol. 29:461- Final Report to grape and wine research & development 471. corporation. CSIRO Plant Industry. 111.

Freeman, B. M., and R. E. Smart. 1976. A root observation McCarthy, M. G. 1997. The effect of transient water deficit laboratory for studies with grapevines. Amer. J. Enol. Vitic. on berry development of cv. Shiraz (Vitis vinifera L.). Aus- 27(1):36-39. tralian Journal of Grape and Wine Research. 3:102-108.

Fregoni, M. 1999. Viticoltura di qualitá. Edizioni McCutchan, H., and K. A. Shackel. 1992. Stem-water po- l’Informatore Agrario S.R.L. Verona, Italy. tential as a sensitive indicator of water stress in prune trees (Prunus domestica L. cv. French). J. Amer. Soc. Hort. Sci. Gaudillère, J. P., C. van Leeuwen, and N. Ollat. 2002. 117:607-611. Carbon isotope composition of sugars in grapevines, an integrated indicator of vineyard water status. Journal of Naor, A., and S. Cohen. 2003. Sensitivity and variability of Experimental Botany. 53(369):757-763. maximum trunk shrinkage, midday stem water potential, and transpiration rate in response to withholding irrigation Girona, J., M. Mata, J. Del Campo, A. Arbonés, E. Bartra, from field-grown apple trees. HortScience. 38:547-551. and J. Marsal. 2006. The use of midday leaf water potential for scheduling deficit irrigation in vineyards. Irrig. Sci. Ojeda, H., A. Deloire, and A. Carbonneau. 2001. Influ- 24:115-117. ence of water deficits on grape berry growth. Vitis. 40(3): 141-145. Hessdörfer, D., A. B. Schwab, and B. R. Gruber. 2013. Ojeda, H., C. Andary, E. Kraeva, A. Carbonneau, and A. Continuous measurements of grapevine water status in Deloire. 2002. Influence of pre- and postveraison water an irrigated vineyard under changing weather conditions. deficit on synthesis and concentration of skin phenolic Proceedings of the 18th International Symposium Giesco, compounds during berry growth of Vitis vinifera L., cv. Porto, Portugal. Shiraz. Am. J. of Enol. Vitic. 53(4):261-267. Idso, S. B. 1982. Non-water-stressed baselines: a key to Ojeda, H. 2007. Irrigation qualitative de précision de la measuring and interpreting plant water stress. Agricultural vigne. Le Progrès Agricole et Viticole. 7:133-141. Meteorology. 27:59-70. Ojeda, H. 2008. Stratégies d’irrigation en fonction des Jones, H. G. 1999. Use of thermography for quantitative particularités et les objectifs du vignoble. Cahier Tech- studies of spatial and temporal variation of stomatal con- nique, Revue Française d’œnologie. 229. ductance over leaf surfaces. Plant, Cell and Environment. 22:1043-1055. Ortega-Farías, S., and C. Acevedo. 2004. Irrigation Sched- uling in Vineyards (VIIth Region of Chile) by Using Time Jones, H. G., M. Stoll, T. Santos, C. De Sousa, M. Chavez, Domain Reflectometry. Acta Hort (ISHS). 646:115-119. and O. M. Grant. 2002. Use of infrared thermography for monitoring stomatal closure in the field: application Ortega-Farías, S., M. Duarte, C. Acevedo, Y. Moreno, and to grapevine. Journal of Experimental Botany. 53:2249- F. Córdova. 2004. Effect of four levels of water applica- 2260. tion on grape composition and midday stem water potential of Vitis vinifera L. cv. Cabernet Sauvignon. Acta Hort. Keller, M. 2005. Deficit irrigation and vine mineral nutri- (ISHS). 664:491-497. tion. Am. J. Enol. Vitic. 56(3):267-283. Pellegrino, A., E. Lebon, M. Voltz, and J. Wery. 2004. Re- Lebon, E., V. Dumas, P. Pieri, and H. R. Schultz. 2003. lationships between plant and soil water status in vine (Vi- Modelling the seasonal dynamics of the soil water bal- tis vinifera L.). Plant and Soil. 266:129-142. ance of vineyards. Funct. Plant. Biol. 30:699-710. Pellegrino, A., E. Gozé, E. Lebon, and J. Wery. 2006. A Loveys, B. R., M. Stoll, P. R. Dry, and M. G. McCar- model-based diagnosis tool to evaluate the water stress thy. 2001. Using plant physiology to improve the water experienced by grapevines in a network of farmers’ fields. use efficiency of horticultural crops. Acta Hort. (ISHS). European Journal of Agronomy. 25:49-59. 537:187-197. Pereira ,L. S., A. Perrier, R. G. Allen, and I. Alves. 1999. Loveys, B. R., M. McCarthy, H. G. Jones, J. Theobold, and Evapotranspiration: review of concepts and future trends. A. Skinner. 2005. When to water? Assessment of plant- Journal of Irrigation and Drainage Engineering ASCE. based measurements to indicate irrigation requirements. 125:45-51. – 50 – Precision Irrigation of Grapevines

Peyrot des Gachons, C., T. Tominaga, and D. Dubourdieu. ment in coaxial transmission lines. Water Resources Res. 2002b. Sulfur aroma precursor present in S-glutathione 16:574-582. conjugate form: Identification of S-3-(hexan-1-ol)-gluta- TONIETTO, J.; CARBONNEAU, A. 2004 A multicriteria thione in must from Vitis vinifera L. cv. Sauvignon Blanc. J. climatic classification system for grape-growing regions Agric. Food Chem. 50:4076-4079. worlwide. Agricultural and Forest Meteorology, Amster- Prieto, J., G. Louarn, J. Perez Peña, H. Ojeda, T. Simon- dam, v.124, p.81-97, 2004. neau, and E. Lebon. 2012. A leaf exchange model that van Leeuwen, C., J. P. Gaudillère, and O. Tregoat. 2001. accounts for intra-canopy variability by considering leaf The assessment of vine water uptake conditions by C- nitrogen content and local acclimation to radiation in 13/C-12 discrimination in grape sugar. J. Int. Sci. Vigne grapevine (Vitis vinifera L.). Plant Cell & Environment. Vin. 35:195-205. 35(7):1313-1328. van Zyl, J. K. 1984. Response of Colombar grapevines to Sammis, T. W., W. R. Rirey, and D. G. Lugg. 1988. Crop irrigation as regards quality aspects and growth. S. Afr. water stress index of pecan. Applied Engineering in Agri- Enol. Vitic. 5(1):19-28. culture. 4:39-45. Williams, L. E., and F. J. Araujo. 2002. Correlation among Saurin, N., H. Ojeda, E. Lucero, R. Mondjou, and T. predawn leaf, midday leaf, and midday stem water poten- Scholasch. 2011. New approach for grapevine irrigation tial and their correlations with other measures of soil and scheduling using sap flow sensors: relationship with pre- plant water status in Vitis vinifera. J. Amer. Soc. Hort. Sci. dawn leaf water potential. American Journal of Enology 127(3):448-454. and Viticulture. 62(3):411A. Williams, L. E., N. K. Dokoozlian, and R. Wample. 1994. Schultz, H. R. 1996. Water relations and photosynthetic Grape. In B. Shaffer and P. Andersen, eds. Handbook of responses of two grapevine cultivars of different geo- Environmental Physiology of Fruit Crops. Vol. I. Tempera- graphical origin during water stress. Acta Hort. (ISHS). ture crops. CRC Press, Inc. Florida, U.S.A. 85-133. 427:251-266. Yunusa, I. A. M., R. R. Walker, B. R. Loveys, and D. H. Blackmore. 2000. Determination of transpiration in irri- Sibille, I., H. Ojeda, J. Prieto, S. Maldonado, J.-N. Laca- gated grapevines: comparison of the heat-pulse technique pere, and A. Carbonneau. 2007. Relation between the with gravimetric and micrometeorological method. Irriga- values of three pressure chamber modalities (midday leaf, tion Science. 20:1-8. midday stem and predawn water potential) of 4 grapevine cultivars in drought situation in the south of France. Ap- plications for the irrigation control. Proceedings XV In- ternational Symposium GESCO. Porec, Croatia. 685-695

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EVIDENCE OF COGNITIVE IMPACT OF ODOUR RECOGNITION TRAINING: INTERMODALITY BY LEARNING WINE AROMAS

Gerard CASAUBON1, David CARRÉ2, María Ines ESPINOZA1, José CHIANALE3, Eduardo AGOSÍN1 and Carlos CORNEJO2

1 Centro de Aromas y Sabores, DICTUC, Pontificia Universidad Católica de Chile 2 Laboratorio de Lenguaje, Interacción y Fenomenología, Escuela de Psicología, Pontificia Universidad Católi- ca de Chile 3 Departamento de Gastroenterología, Facultad de Medicina, Pontificia Universidad Católica de Chile

Recent evidence of the impact of olfactory sensory train- terms, trained participants increased the total answer time ing reveals how circumscribed it is, particularly in con- (t(107)=-2.971; p=.004), number of topics mentioned noisseurs (Tempere, Cuzange, Bougeant, de Revel & Si- (t(107)=-3.733; p=.000) and intermodality level (t(107)=- card 2012). Nonetheless, studies have shown that learning 1.926; p=.050) of their verbal descriptions for abstract im- to tell aromas apart is rather a multisensory cognitive task ages though not for well-defined pictures (Figure 3). In (Booth, Kendal-Reed & Freeman 2010) involving visual both cases, the control group showed no differences. Fur- and tactile perceptions (Sugiyama et al. 2006). To inves- thermore, intermodality was positively correlated to sen- tigate these ideas, we conducted an experimental study sory triangular recognition performance (r=.58, p=.029) combining sensorial and psychological data in order to and showed an association trend with ranking recognition assess whether odour recognition training in the wine ma- (r = .51, p = .068). trix promotes multisensory cognition, i.e., intermodality.

A total of 18 laypersons (housewives aged 35 to 45 [?◊? = Significance of the study 39.2] with technical-level education and no previous sensory training or wine sensory education) were selected to These multilevel results lead us to think that olfactory be trained according to the ISO 8586-1 standard for wine training not only teaches people to recognize wine aro- aroma sensory evaluation. They were trained using state- mas, but also has a broader impact on domains suppos- of-the-art descriptive analysis methodologies (Murray et edly unrelated to olfaction, e.g., how to describe visual al. 2001) to identify 15 sensory attributes (Table 1). Prior stimuli. These results suggest new frontiers in sensory to and after the 12 training sessions, the participants were science, particularly new opportunities in wine sensory asked to verbally describe various images, from clearly education for professionals and consumers alike. Sensory defined pictures to abstract illustrations (Figure 1). A sec- science can play an active role in cognitive development ond, untrained group was assessed in exactly the same among the general public, and the wine industry can help fashion to serve as the control group. Results showed that to face this challenge. sensory training increased sensory skills (i.e., accuracy and repeatability) as well as the ability to discriminate References consistently between wine aroma profiles over several samples. The RANOVA from the formal QDA results for 6 Murray, J. M., C. M. Delahunty, I. A. Baxter. 2001. De- wines and 3 replicates showed that 14 out of 15 attributes scriptive sensory analysis: past, present and future. Food were discriminant, i.e., p<0,05 (Figure 2). In cognitive Research International. 34:461–471 – 53 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

Booth, D. A., M. S. Kendal-Reed, R. P. J. Freeman. 2010. Tempère, S., E. Cuzange, G. de Revel, G. Sicard. 2012. A strawberry by any other name would smell as sweet, Explicit sensory training improves the olfactory sensitivi- green, fruity and buttery. Multisensory cognition of a ties of wine experts. Chemosensory Percept. 5:205–213 food aroma. Appetite. 55:738-741 DOI: 10.1007/s12078-012-9120-1.

Sugiyama, H., S. Ayabe-Kanamura, T. Kikuchi. 2006. Are International Organization for Standardization. 1993. olfactory images sensory in nature? Perception. 35:1699- International Standard – ISO 8586-1: Sensory Analy- 1708. sis – General Guidance for the Selection, Training and Monitoring of Assessors – Part 1: Selected Assessors. Copenhagen: Dansk Standard. Table 1. Sensory descriptors and aromatic standards employed

Descriptor Standard used Prune 100 grams of dry prune, macerated for 24 hours in a hydro-alcoholic solution Mushroom 1-Octen-3-ol; 0.0398 ppm Coffee 5 grams of instant coffee in 250 ml of hydro-alcoholic solution Cloves Eugenol; 0.4 ppm Raspberry Raspberry, whole fresh fruit Eucalyptus 5 drops of eucalyptus essence in 250 mL of hydro-alcoholic solution Chocolate 10 grams of bitter chocolate in 250 mL of hydro-alcoholic solution Bell pepper 2-isobutil-3-metoxipyrazine; 0.8 ppm Pepper 5 grams of black pepper in 250 mL of hydro-alcoholic solution Vanilla Vainillin; 30.4 ppm Coconut Whiskey lactone; 0.2 ppm Asparagus 100 grams of asparagus macerated 24 hours in hydro-alcoholic solution Tobacco 10 grams of tobacco in 250 hydro-alcoholic solution Woody 25 grams of wood chips, macerated 24 hours in hydro-alcoholic solution Smoky 5 drops of methyl guaiacol in 250 ml of hydro-alcoholic solution

“It has several different “That is what I perceive of shapes and colours, like this “Crispiness, warmth, everything, (the painting) black area, that I do not like “Raspberries” summer. Sun, family…, feels like a bit of a mess, much. But I do like those joy, all things positive.” a city, contamination . . . blues, yellows. Those are messy in general.” colours that I would use.”

Figure 1. Examples of verbal descriptions of images, pre and post workshop interviews, from clearly defined pictures to abstract illustrations.

– 54 – Evidence of Cognitive Impact of Odour Recognition Training: Intermodality by Learning Wine Aromas

Bell pepper (p: 0.00)

Mushroom (p: 0.00) Asparagus (p: 0.06)

Pepper (p: 0.00) Eucalyptus (p: 0.00)

Coconut (p: 0.00) Tobacco (p: 0.00)

Smoky (p: 0.00) Raspberry (p: 0.00)

Clove (p: 0.01) Prune (p: 0.00)

Chocolate (p: 0.00) Woody (p: 0.00)

Coﬀee (p: 0.01) Vanilla (p: 0.00)

Merlot Casillero del Diablo 2010 Carmenere Casillero del Diablo 2010 Cabernet Sauvignon Casillero des Diablo 2010 Syrah Sol de Chile 2008 Carmenere Cremashi Furlotti 2010 Carmenere Indo 2009

Figure 2. Quantitative descriptive analysis from trained panel data (6 red wines, 3 replicates) showing training process success through discriminant ability for 14 out of 15 attributes (RANOVA, p<0,05)

Cognitive Variations Previous After

Total 44.2 49.4* Answer Time Topics 2.87 2.95* Mentioned

Intermodality 3.27 3.5* Level

Figure 3. Cognitive variables measured prior to and after training that show significant differences, 18 panelists (total answer time t(107)=-2.971; p=.004), number of topics mentioned (t(107)=-3.733; p=.000) and intermodality level (t(107)=-1.926; p=.050).

– 55 –

PHENOLIC MATURITY: CONCEPT, METHODOLOGY AND OENOLOGICAL IMPLICATIONS

Fernando ZAMORA

Department of Biochemistry and Biotechnology, Faculty of Oenology Universitat Rovira i Virgili, Tarragona, Spain

The concept of “phenolic maturity” is not new. In fact, it increase during the ripening process whereas seed tannins has been a subject of great interest for winemakers over decrease (Ribéreau-Gayon et al. 1999). the past two decades. There is no doubt that the concen- As seen in Figure 2, the astringency of skin tannins tends tration and extractability of anthocyanins in the grape to decrease, while that of seed tannins is kept constant skin, as well as the proportion of seed tannin, are some throughout the maturation process. In general, unripe of the main factors affecting the future quality of red wine grapes have fewer tannins than well-ripened grapes, but (Ribéreau-Gayon et al. 1999). For this reason, in recent the contribution of ripe grapes to astringency is tought to years there has been talk – and we will continue talking be greater as they can release more seed tannins (Delteil – about the need for effective methods to determine the 1998, and Ribéreau-Gayon et al. 1999). actual level of phenolic maturity in the grapes, to provide more appropriate criteria for deciding the optimum 90 harvest date (Glories and Agustin 1993, Lamadon 1995, Seeds Izcara and González 2001, and Zamora 2002). 80

To illustrate these concepts, it is necessary to show the 70 evolution of phenolic compounds from grapes throughout 60 Skins the ripening process (figure 1). Gelatine index (%) index Gelatine 50 Skin tannins Veraison Maturity

Figure 2. Evolution of the astringency of the tannins throughout Anthocyanins the maturation process The main reason why seed tannins are more astringent Seed tannins than skin tannins is related to the fact that the tannins of the seeds and skins do not have the same composition, as shown in figure 3. Basically, the tannins from the skins Veraison Flesh maturity are rich in prodelphinidin and have a small proportion Figure 1. Evolution of phenolic compounds throughout the maturation process of gallate units, while the seeds are particularly rich in epicatechin gallate, which confers higher astringency on The concentration of anthocyanins can be seen to in- them (Cheynier 2002). crease during the maturation process up to maximum value, followed by a slight decrease. Meanwhile skin tannins

– 57 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

mg/kg mg/kg grapegrowers and winemakers know that observing the Skins Seeds colour of seeds is probably the best way to determine if 4000 1000 the grapes are really ripe. Figure 4 shows the changes in seed colour throughout ripening. 800 3000 ܨ ܩ ܪ ܫ 600 Veraison 2000 400 1000 200 ܮ 0 ܭ ܬ 0 Optimal maturity Cariñena Cabernet- Cariñena Cabernet- Sauvignon Sauvignon

Prodelphinidins Procyanidins Galloylated Procyanidins Figure 4. Evolution of seed colour throughout the maturation Figure 3. Distribution of grape proanthocyanidins process In summary, unripe grapes have a low concentration of It is clear that when seeds have a dark brown colour, the anthocyanins, which are also less extractable. Similarly, grapes are ready to be harvested. unripe grapes have a high concentration of tannins from seeds, so if you force maceration in order to extract 2. Methods based on physical measurements of enough colour, herbaceous and astringent tannins will berries be also extracted. In contrast, well-ripened grapes have a This group includes several methods based on different high concentration of easily extractable anthocyanins and physical properties of grapes, such as texture and colour. will produce wines with a soft body and tannins. Methods based on texture (Rio Segade et al. 2008) obtain The degree of the phenolic maturity of the grapes is clearly good correlations between grape maturity and the texture a key factor for red wine quality, and therefore the harvest properties of grapes. However, applying this procedure date should be determined using this criterion. to determine the harvest date is not imaginable, because it is a slow and laborious process requiring very specific In recent years, several methodologies for the determina- equipment. Methods based on colour measurements are tion of phenolic maturity have appeared in the literature faster, but only give an idea of skin maturity and not of (Dupuch 1993, Lamadon 1995, Venencie et al. 1997, Iz- seed maturity. cara and González 2001, Dubernet et al. 2000, and Ce- lotti et al. 2007), but probably the most used is the methodology described by Professor Yves Glories (Glories and 3. Methods based on the preparation of an Agustin, 1993). Overall, the methods for measuring phe- extract which reproduces the wine, and later nolic maturity can be classified into three groups: analysis • Methods based on tasting berries Methods based on the preparation of an extract are cur- • Methods based on physical measurements of berries rently the most used. • Methods based on the preparation of an extract that re- However, all these methods are weighty in their imple- produces the wine, and later analysis. mentation, and the results obtained do not always reflect what is happening in the tank during winemaking. In fact, 1. Methods based on tasting berries all these methods consist of three steps:

Methods based on tasting berries are very useful, because Extraction phase Should quickly and efficiently repro- we obtain a good idea of the real maturity of grapes by duce the release of phenolic compounds that occurs dur- tasting them. However, these methods require a great deal ing winemaking. of experience and laborious sampling. They are applica- Analytical phase Should try to determine the parameters ble mainly in small wineries with their own vineyards or of interest for the future wine quality. at least very controlled vineyards. It is particularly difficult to establish parameters with these methods, but all Interpretation of results Should allow the following: – 58 – Phenolic Maturity: Concept, Methodology and Oenological Implications

Table 1. The existing methods Method Extraction Phase Analysis Time/Difficulty Grinding with mixer Maceration for 4 hours with Glories and Agustin,1993 Extractable anthocyanins +++++ two solutions at pH = 1 and pH = 3.2 Grinding with mixer A520 ITV (Dupuch 1993) Maceration for 1 hour with +++ A280 HCl/ethanol solution Grinding with mixer Maceration at high Probable colour Cromoenos (Gracia) temperature with a special + Phenolic maturity index equipement and with commercial solutions Grinding with mixer Anthacyanins (A520) The AWRI method Maceration for 1 hour with ++++ TPI (A280) and Tannins ethanol 50% Grinding with mixer and FTIR Dubernet et al. 2000 +++++ centrifugation Multiple parameters

• Identification of the optimal time of harvest date is probably the one designed by Professor Yves Glo- • Sorting of the grapes according to their actual quality ries. Figure 5 illustrates this procedure schematically. • Adaptation to winemaking to the phenolic maturity The anthocyanins in the extract at pH 1.0 are considered level of the grapes. to be the total anthocyanins present in grapes, while the Each of the steps must be differentiated, because they are anthocyanins in the extract at pH 3.2 are considered to independent and largely determine the reliability and robustness of the method.

The extraction phase is key, as it is involved Representative sampling in an accelerated process of solubilization of 2 batches of 200 berries phenolic compounds that will take place later in the tank. This is probably the determin- Batch A Batch B ing factor in all the methodologies, as it is not extracting anything that contains grape, but rather solubilizing what the future will have. Press and determine: The analytical phase analyzes the parameters Weight of 100 berries Homogenize in a Sugar content conventional blender considered most suitable from the extract ob- Titratable acidity and pH tained above. It is important to consider that if the extraction is not representative, nothing we analyze will be useful. The objective is not to know the composition of the extract, 50 g of homogenized berries 50 g of homogenized berries + + but to know what these grapes are going to same volume of same volume of generate. Therefore, the reliability of all the solution at pH=1 solution at pH=3.2 methods is largely determined by the extraction procedure. Shake manually and wait for 4 hours Table 1 summarizes the characteristics of Filter or centrifuge the methods currently used to determine the phenolic maturity of the grapes. Determine the concentration Determine the concentration As shown in this table, there are several pos- of anthocyanins of anthocyanins and A280 sible methods, but the most widely used to Figure 5. The Glories Method (1993)

– 59 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY be those which will be extracted during winemaking. This In theory, the potential anthocyanins should increase dur- method also allows us to obtain two other parameters ing the ripening process to reach a maximum value. The (Figure 6). extractable anthocyanins should also increase. The EA% and MP% should decrease as the level of maturity of the Potential Anthocyanins = ApH1 grapes increases. The EA generally ranges between 70% Extractable Anthocyanins = ApH3.2 and 20%, while the MP usually ranges between 60% and 10%. The optimal harvest date should, according to Pro- fessor Glories, be when the potential anthocyanins reach Anthocyanins Extractibility very high values (more than 1000 mg/L), and when the ApH1 - ApH3.2 EA% = x 100 levels of EA% and MP% are very low (below 30% in both ApH1 cases).

Seed Tannin Contribution The methodology described by Professor Glories is laborious and difficult to apply in wineries. For this reason, oth- A280 - (ApH3.2 x 40) MP% = x 100 er approaches have emerged to try to simplify the process. A280 Such is the case of the ITV method, which is faster, and

Figure 6. Analytical parameters of the Glories Method (1993) especially the recent Cromoenos method, which permits EA% (percentage of extractable anthocyanins) represents rapid determination (under 10 minutes). the percentage of anthocyanins that will be extracted, and However, the main problem with all three methods is MP% represents the percentage of tannin released from knowing their degree of reliability. Most research is limit- seeds. ed to comparing the methods, not trying to verify whether

Total Anthocyanins Extractable Anthocyanins 1200 1400 1000 1200 1000 800 800 600 600 400 400 200 200 Anthocyanins (mg/L) Anthocyanins (mg/L) Anthocyanins 0 0 0 500 1000 1500 2000 0 500 1000 1500 Anthocyanins pH:1 (mg/L) Anthocyanins pH:3.2 (mg/L) Anthocyanins = 0.52 x Anthocyanins pH 1 + 59.6 Anthocyanins = 0.96 x Anthocyanins pH 3.2 + 45.9 r2 = 0.7897 r2 = 0.8809

TPI Colour Intensity 70 25

60 20

50 15 CI TPI 40 10

30 5

20 0 20 30 40 50 60 0 5 10 15 20 Predicted TPI Predicted Colour TPI = 0.75 x predicted TPI + 11.31 CI = 1.11 x Predicted colour - 0.96 r2 = 0.8839 r2 = 0.8489

Figure 7. Predictive effectiveness of the Glories method – 60 – Phenolic Maturity: Concept, Methodology and Oenological Implications they are truly effective for predicting the colour and/or With the Cromoenos method, the correlation was much phenolic composition of future wines. For this reason, our better than in the previous case. It can be concluded that research group considered it necessary to perform a study among these three methods, the Glories method generates of the real effectiveness of each of these methods. the best correlation coefficient between the measured and To do this, four cultivars (Tempranillo, Garnacha [Gr- predicted anthocyanin concentration in wine. However, enache], Merlot and Cabernet Sauvignon) were harvested it is laborious and difficult to apply in the winery. The in 2007 at three maturity levels (three, five and seven ITV method does not seem to be appropriate, because it weeks after veraison). In all cases, winemaking was per- creates a very low correlation coefficient and therefore formed in triplicate, and the wine colour and composition does not correctly predict the colour intensity of future were compared to that predicted by the Glories, ITV and wines. The Cromoenos method presents a reasonable cor- Cromoenos methods (Kontoudakis et al. 2010). Figure 7 relation coefficient between the predicted colour and that show the results obtained by the Glories method. obtained in the wine, and also has the advantage of being very quick. As can be seen, the Glories method provides reasonably good results in terms of the relationship between extract- It should be noted that the implementation of a harvest able anthocyanins and the real anthocyanin concentration date decision-making system based on phenolic maturity in wine. But this is not true for the total polyphenol index is very complicated. Practical experience in the applica- (TPI). Figure 8 show the results obtained by the ITV method. tion of this methodology indicates significant variability The ITV method results were somewhat disappointing be- in the results. In fact, many wineries have tried it with cause the correlation coefficients were very low. Figure 9 inconsistent results. The problem is that this methodology, (next page) shows the results obtained with the Cromoe- as described, must be applied with great rigour. If not, it nos method. can lead to erratic results that mislead the winemaker.

Colour intensity Anthocyanins 15 1200 1000 10 800 600

Wine CI Wine 5 400 200

0 anthocyanins (mg/L) Wine 0 0 5 10 15 0 200 400 600 Predicted CI Anthocyanins ITV (mg/L) Wine CI = 0.72 x Predicted CI + 3.83 Wine anthocyanins = 0.64 x Predicted anthocyanins + 45.2 r2 = 0.3879 r2 = 0.8259

Coulour intensity 70 60 50 40 CI 30 20 10 0 0 40 80 120 160 Predicted TPI Wine TPI = 1.36 x predicted TPI - 16.6 r2 = 0.8028

Figure 8. Predictive effectiveness of the ITV method – 61 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

The subject is therefore still up for debate. Existing meth- phenolic maturity, which would serve as a criterion for ods for determining the degree of phenolic maturity must separating qualities and would set a price for the grapes be optimized first. On the one hand, the conditions in according to their actual quality. In addition, the wine- which the sample is prepared must be specified in greater maker, knowing the actual level of phenolic maturity, detail, and on the other hand, systems need to be de- could apply different strategies to obtain the most suitable signed to automate the process to make it faster and more degree of extraction (Delteil 1995, and Ribéreau-Gayon efficient. et al. 1999).

Realistically, another necessary consideration is that using phenolic maturity as a tool for deciding the harvest date References is, in many cases, utopian. The harvest, as we all know, is Celotti, E.,S. Dell’oste, P. Fiorini, and G. Carceri. 2007. conditioned by many factors, including the weather, the Une nouvelle méthode pour l’évaluation des polyphé- health status of the grapes, the capacity of the winery, and nols des raisins rouges. Rev. Œnol. 125:23-27. so on, which, in the end, are unfortunately more impor- Cheynier, V. (2002). Oxygen in wine and its role in tant than the maturity of the grapes. Only wineries that phenolic reactions during aging. Uses of gases in wine- use grapes from their own vineyards could afford to use making. Eds: M. Allen, S. Bell, N. Rowe and G. Wall. this criterion. Proceedings of the Australian Society of Viticulture and Nevertheless, determining of phenolic ripeness can be Oenology Seminar, October 2002, Adelaide.ASVO, very useful as a monitoring tool at the winery gate. The Adelaide. grapes could be classified according to their degree of

Colour intensity Anthocyanins 25 1200

20 1000 800 15

CI 600 10 400 5 200

0 anthocyanins (mg/L) Wine 0 0 5 10 15 20 0 500 1000 1500 2000 Predicted colour Predicted anthocyanins (mg/L) CI = 1.20 x Predicted colour + 0.51 Wine anthocyanins = 0.67 x Predicted anthocyanins + 2.2 r2 = 0.8869 r2 = 0.9060

Coulour intensity TPI 25 70 60 20 50 15 40 CI 10 TPI 30 20 5 10 0 0 0 5 10 15 20 0 40 80 160 200 240 Predicted colour Predicted TPI CI = 1.50 x predicted colour - 2.28 TPI = 0.19 x Predicted TPI - 1.49 r2 = 0.9517 r2 = 0.8180

Figure 9. Predictive effectiveness of the Cromoenos method – 62 – Phenolic Maturity: Concept, Methodology and Oenological Implications

Delteil, D. 1995. Les macérations en rouge: L’art du détail. Rev. Œnol. 77:23-25.

Dubernet, M., V. Dubernet, M. Lerch, S. Coulomb, and I. Traineau. 2000. Analyse objective de la qualité des vendanges par spectroscopie infrarouge à transformée de Fourier et réseaux de neurones. Rev. Fran. Œnol. 185:18- 21.

Dupuch, V. 1993. Appréciation de la matière phénolique des vins rouges ; application à la détermination de la date de récolte. Actes du Colloque Journée technique du CIVB. Bordeaux. 62-69.

Glories, Y., and M. Agustin. 1993. Maturité phénolique du raisin, conséquences technologiques; application aux millésimes 1991 et 1992. Actes du Colloque Journée technique du CIVB. Bordeaux. 56-61.

Izcara, E., and M. L. González. 2001. Análisis de mé- todos rápidos de extracción para seguir la maduración fenólica de la uva. Enólogos. 14:14-18.

Kontoudakis, N., M. Esteruelas, F. Fort, J. M. Canals, and F. Zamora. 2010. Comparison of methods for estimating phenolic maturity in grapes: Correlation between predicted and obtained parameters. Analytica Chimica Acta. 660:127-133.

Lamadon, F. 1995. Protocole pour l’évaluation de la richesse polyphénolique des raisins. Rev. Œnolog. Tech- niq. Vitvinic. Œnol. 76:37-38.

Ribéreau-Gayon, P., Y. Glories, A. Maujean, and D. Dubourdieu. 1999. Phenolic Compounds. Handbook of Enology, Vol. 2. The Chemistry of Wine Stabilization and Treatments. John Wiley & Sons, Ltd, Chichester. 129-186.

Rio Segade S., E. Soto Vázquez and E. Díaz Losada, 2008. Influence of ripeness grade on accumulation and extractability of grape skin anthocyanins in different cultivars. J. Food Comp. Anal., 21, 599-607.

Venencie, C., M. N. Uveira, and S. Guiet. 1997. Maturité polyphénolique du raisin ; mise en place d’une méthode d’analyse de routine. Rev. Fran. Œnol. 167:36-41.

Zamora, F. 2002. La madurez fenólica; Un tema abierto. Enólogos. 18:24-28.

– 63 –

IMPACT ON AGRONOMIC PARAMETERS IN VINES AND WINE QUALITY OF FOLIAR TREATMENTS WITH SPECIFIC FRACTIONS OF YEAST DERIVATIVES

Javier TÉLLEZ, Elisa GARCÍA, Emilio PEIRO, Vanesa GONZÁLEZ, José Ramón LISSARRAGUE

Grupo de Investigación en Viticultura, Universidad Politécnica de Madrid, Spain [email protected]

1. Introduction The concept of phenolic maturity in grapes is linked to the concentration of anthocyanins in the skin, their extract- Winemakers and grape growers are constantly looking ability and the tannin content, as well as the concentra- for opportunities to improve wine quality. Producing high tion of condensed tannins in the seeds. quality fruit for wine production is challenging and dependent on many factors, including the regional climate, Compounds of a phenolic nature greatly impact the co- seasonal variations in precipitation and the temperatures lour, aroma, taste and organoleptic characteristics of the in the growing season. As a result, wineries are often re- must, and therefore, of the wine (de la Fuente et al. 2007). quired to work with unbalanced grapes, overcoming such Anthocyanins and tannins are the main representatives of obstacles as poorly ripened fruit, high pH, low acidity and the phenolic compounds present in grapes and red wines. wines that will lose quality quickly. High quality wine Anthocyanins are the main colour components in red production in the cellar starts with high quality grape pro- wines (Jackson and Lombard 1993), and tannins impart duction in the vineyard. bitterness and astringency (Harborne 1984). The union of anthocyanins and tannins forms polymers that provide Many producers would like to get grapes with moderate stable pigments necessary to maintain the stability of the sugar content in the pulp, good acidity, low pH and good colour of red wines over the long term. skin maturity, skin that is both phenolic and aromatic and, if possible, mature seeds. During the early stages of berry ripening, the amount of anthocyanins increases. At ripening, the accumulated To try to meet these challenges to wine quality, Lallemand amount of anthocyanins reaches a maximum then re- has developed a series of products that stimulate pheno- mains relatively constant or declines. Several studies have lic maturity and increase the synthesis of grape aroma shown a decrease in anthocyanin content in the later stag- precursors through the foliar application of yeast deriva- es of ripening (e.g., Somers 1976, Keller and Hrazdina tives. These yeast derivatives are designed for use as per 1998, and Holt et al. 2010). WO/2014/024039 patent-pending foliar application technology. Meanwhile, it appears that tannin synthesis occurs early in berry development (Downey et al. 2003). Studies by Two different yeast derivative compositions, RD-LM for Bogs et al. (2005) suggest that tannin is being synthesized red grape varietals and RD-LA for white grape varietals, even before the berry has set. Tannins increase at a steady were tested to evaluate their ability to stimulate phenolic rate from fruitset to a peak around veraison. Some studies maturity and enhance the synthesis of grape aroma pre- show a decrease – for example for Shiraz, a 60% decrease cursors during ripening. Evaluation of wine tasting was over a range of 6° to 30°Brix (Downey et al. 2003) – while done by a trained expert tasting panel. others have shown that tannin content remained essen- – 65 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY tially constant from veraison to harvest, for Cabernet Sau- Accordingly, many techniques have been applied to vignon and Pinot Noir, for example, which are essentially improve the content of these factors in the berries. The constant from veraison to approximately 24°Brix (Harb- most common techniques are related to agricultural tech- ertson et al. 2002). In addition, cultural practices and cli- niques, as thorough studies have been conducted on the matic conditions are likely to influence the metabolism of impact of such factors as the optimal exposure of clusters tannins in skins (Iland et al. 2011). (Carbonneau and Costanza 2004), the canopy microclimate (Jackson and Lombard 1993), the optimization of From this, we can take away that the harvest moment is a key leaf surface areas (Bonnisseau and Dufourcq 2004), mod- factor in the degree of phenolic maturity. Grapes that have erate hydric stress (Seguin 1975, Bravdo et al. 1985, and not reached phenolic maturity will produce wines that are Carbonneau 1987) and the effect of nitrogen fertilizer not so balanced and have a strong sensation of astringency. (Bell and Henschke 2005).

Regarding aroma, clearly aroma is one of the factors that In an attempt to improve the phenolic content in the grape, most determines the quality of a wine. Aroma compounds, other mechanisms have recently garnered attention, such which come from the secondary metabolism of the vine, as the use of elicitors – phytochemicals that do not kill include terpenes, norisoprenoids, thiol precursors and me- pathogens per se but rather trigger mechanisms that im- thoxypyrazines. These compounds contribute to the vari- prove plant resistance to pathogens, including an increase etal character that typifies the wine. This varietal character in phenolic compound levels (Vitalini et al. 2011). comprises, on one hand, the free volatile compounds of direct aromatic expression, which are few in number, and The concentration and quality of phenolic compounds, as on the other hand, the aroma precursors, which are non- well as aroma precursors, are parameters that depend on volatile components freed during aging or thanks to the the variety being studied. Therefore, these trials have been done on two common viticultural varieties with great oe- metabolic activity of yeasts (Jackson 2008). Some research nological potential: Shiraz and Sauvignon Blanc. shows that glycosidic aroma precursors are not present in all grape varieties, and when they are present they are not Our studies have focused on trying to determine the be- in the same concentrations (Reyero et al. 2000, Garcia- haviour and response mechanisms of vines to the appli- Moruno et al. 2000, and Reynolds and Wardle 1997). cation of yeast derivatives, in order to verify and quantify agronomical and oenological interest, showing that the During the period of berry formation, the concentration studied applications have an impact on the quality of the of the free monoterpenes and most of the bound ones fell final wine. This project aimed to study the effect of yeast to low levels. From veraison onwards, only the linalool, derivatives on the vines – evaluating responses in variet- diendiol and the pyran ring linalool oxides accumulated ies with great oenological potential, verifying the effect of to any significant extent. These continued to a maximum the yeast derivative composition, doses and timing, study- of about 24°Brix, and then declined. ing the relationship between the response and the applied In grape berries, norisoprenoid levels are low prior to ve- dose – then come to a conclusion regarding cause–effect raison and increase after veraison (Razungles et al. 1993 relationships. We also verified whether the effect of yeast and 1996, Marais et al. 1991, Baumes et al. 2002, Bindon derivative products on the grapes and wine is manifested 2004, and Bindon et al. 2007). The pattern of change in according to the time of harvest and/or the ripeness of the these compounds and carotenoids led researchers to pro- grapes. pose that the formation of norisoprenoids is linked to the Yeast derivative applications tested in the vineyard were ef- degradation of carotenoids. fective for defining different wine qualities, without affecting Methoxypyrazine content increases during berry forma- yield or other agronomical parameters. The wine descriptors tion, reaches a peak around veraison, then decreases dur- were evaluated as more important than the control plots. ing berry ripening (Boss et al. 2008, Ryona et al. 2008, and Reynolds 2010). Typically, levels of methoxypyrazines are 2. Material and methods higher in berries from vines grown in cool climates than 2.1 Vineyard Location. Plant Material and those from warm and hot climates (Boss et al. 2008). Experimental Design There are many factors that affect phenol synthesis and This experiment was performed in Finca Constancia (To- aroma precursors in the vine, including light, temperature, ledo, Spain) in 2013. The area presents a warm climate altitude, soil type, water, nutritional state, microbial inter- with marked seasonal variation and a period of noticeable actions, pathogens, growth regulators and defoliation. summertime drought. In 2013, there were 2,135 growing – 66 – Impact on Agronomic Parameters in Vines and Wine Quality of Foliar Treatments with Specific Fractions of Yeast Derivatives degree days (GDD) and 384 mm of rain. Vineyard soils Physiology are inceptisols and alfisols, according to the USDA. To determine the effect of the experimental products on The study was carried out on grapevines planted in 2002, the physiological activity of the plant, foliar water po- with a distance of 2.4 m between rows and 1.2 m be- tential (f) and the exchange of gasses in the atmosphere tween plants within the row. The rows are orientated were measured on individual leaves. North–South, and the trellis system is Vertical Shoot Posi- The measurements took place at two moments of the day, tioned with bilateral cordon and spur pruning. at optimal environmental conditions for photosynthetic The plant material used to perform the trials was made up activity and at solar noon. Optimal conditions for pho- of vines from two different cultivars, the Shiraz clone 470 tosynthesis were determined according to Sánchez-de- grafted on 1103-P and the Sauvignon Blanc clone 700 Miguel (2007). grafted on 110-R. These measurements were taken twice during the cycle. All treatments were applied in four repetitions arranged At pre-veraison five leaves of each treatment were sam- in a completely randomized design. Vines were sprayed pled and at full maturity five leaves of each treatment with a water solution of yeast derivatives at the begin- were sampled. ning of veraison (5 to 10% of veraison then again 10 days The foliar water potential was evaluated using a Scholan- later). The solutions applied were the RD-LM product at a der pressure chamber (Model 3000 Soil Moisture Equip- rate of 1 kg/ha on Shiraz vines, and the RD-LA product at ment Corp., Santa Barbara, CA, USA) with a reading reso- 3 kg/ha on Sauvignon Blanc. In both cases, 300 L/ha was lution of 0.01 MPa. applied with a 16-litre capacity Matabi model E+ electric motor sprayer, which ensures constant pressure. Via an open system of infrared gas exchange measurement (IRGA) (LI-6400 portable photosynthesis system from LI- 2.2 Measurements COR®, Lincoln, Nebraska, USA), the instantaneous rate of Vegetative Growth CO2 (An) assimilation in μmol CO2/m2 leaf and stomatal Pruning Weight and Shoot Weight conductance (gs) in mol H2O/m2 leaf was obtained. This The pruning weight (PW) was measured in five plants of measurement was taken only on the Shiraz cultivar. average vigour at each repetition. The number of shoots Yield Components (Three Harvests) per vine was counted, and the shoots removed were Harvest Weight weighed with a 5 kg maximum weight and 50 g precision Pesola model 8.004 dynamometer. Two average-sized The harvest weight was determined at three different mo- shoots were taken in each repetition, then weighed on a ments, defined as the average °Brix of the different repeti- scale with a sensitivity of 0.01 g (OHAUS Adventurer™ tions from the same cultivar. The °Brix intervals that were Pro model AP AV412) and were kept in separate labeled set to decide the times of harvest were equivalent to an bags. These bags were placed on a stove at 70°C until a early harvest, an industrial harvest and an overripe har- constant weight was reached. vest.

Vegetative/Productive Balance Harvest weight was measured in six plants by experimental plot and time of harvest. Shoots and bunches were Dry Weight counted for each vine, and the bunches from the six plants Two representative vine shoots of average vigour were were weighed on a 30 kg maximum 5 g precision elec- chosen from each repetition in each of the experimen- tronic scale (Calitrol Control Gram model PM-30, Bar- tal plots for a total of eight per treatment. Stems, leaves celona, Spain). Using these data and the average weight and bunches were weighed on a scale with a sensitivity of the berries, the following yield components were de- of 0.01 g (OHAUS Adventurer™ Pro model AP AV412), termined: berry weight, kg/vine, number of bunches per to obtain their fresh weight. Each part was then kept in a shoot and bunch weight. separate labeled bag and placed on a stove at 70°C with forced ventilation until a constant weight was reached. Evolution of the Berry Composition During the Ripening Once dry, each sample was weighed to obtain the dry Period weight and percentage of water. Technological Maturity The humidity level of the stems and bunches was applied Weekly samplings were performed of 100 berries per el- to all stems and bunches in the repetition. emental plot from pre-veraison to time of harvest. Each – 67 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY sample was weighed on a scale with a sensitivity of 0.01 g 1.1.2 Sensory Analysis (OHAUS brand Adventurer Pro Model AP AV412) to de- The wines from the two experiments were subjected to termine average berry weight. The must from these 100 sensory evaluation. These were performed by a group of berries was extracted with a strainer and, after centrifuga- 11 professional tasters made up of professional oenolo- tion, the supernatant material was collected for analysis of gists and researchers from the viticulture research group total soluble solids (°Brix), pH and total titratable acidity. at the Universidad Politécnica de Madrid.

The total soluble solids were measured using a portable The method of analysis involved triangle taste tests that digital refractometer (PALETTE WM-7, ATAGO Inc., Kirk- showed whether or not the tasters were able to perceive land, Washington, USA), with results shown in °Brix; total a difference in treatments. This procedure allows informa- titratable acidity was measured using an automatic titrator tion to be collected on sensory differences and similarities (736 GP Titrino, METROHM AG, Herisau, Switzerland), for a wide variety of products (Blancher et al. 2007 and with the values shown in g tartaric acid/L; and pH was Cartier et al. 2006). determined using a pH meter (micropH 2001, CRISON, Barcelona, Spain) that had been previously calibrated. The results of the triangle taste tests were calculated statis- tically according to the tables of Roessler et al. (1948) for a. Phenolic Maturity levels of significance of 5%, 1% and 0.1%. Samples were taken of 150 berries during each of the After the triangular tests, treatment wines that were sig- three harvests from every one of the experimental Shiraz nificantly different according to the aforementioned un- plots and then triturated in a blender (Royal Blender Turbo derwent a descriptive test to determine which wine the 10-speed, Princess). tasters preferred. The extraction method proposed by Glories and Augus- 1.1.3 Analysis of Results tin (1993) was used to calculate the total polyphenol index (TPI) and the concentration of total and extractable Due to its experimental design, statistical analysis of a anthocyanins. Two standards were applied: one at pH 1 large part of the results was performed through variance (HCl 0.1 N) for extracting all anthocyanins and another at analysis. The significance of the variance analysis was de- pH 3.2 (5 g/L tartaric acid solution) for extracting the ex- termined for probability levels p<0.05 (*), p<0.01 (**) y tractable anthocyanins. Absorbency measurements were p<0.001 (***). Whenever this showed significant effects taken at 280 nm and at 520 nm with a spectrophotometer of treatment, the averages were compared using Duncan’s (J.P. Selecta, SPECTROPHOTOMETER UV-2005). Tannins multiple range test for a probability level of p<0.05. The were extracted from the berry using methodology from program SPSS, version 18.0 (SPSS Inc. Chicago, Illinois) the Standard Methods of the Australian Wine Research In- was used for all statistical analyses. stitute (AWRI) (Iland et al. 2004). 2. RESULTS AND DISCUSSION Quantification of the tannins was performed using the method of Methyl Cellulose Precipitation (MCP) (Sarneck- All media data obtained in the field and laboratory during is et al. 2006, and Mercurio and Smith 2008). This reading the campaign was reported and compared with data ob- was obtained by using a spectrophotometer (J.P. Selecta, tained by other authors, with particular attention paid to SPECTROPHOTOMETER UV-2005). differences possibly attributable to different yeast derivative treatments. See table 1. 1.1.1 Fermentations Separate fermentations were conducted for the 16 rep- 2.1 Vegetative Growth etitions during the three specified harvests, resulting in The most reliable estimator of plant vigour is pruning a total of 48 micro-fermentations. Fermentations were weight (Huglin 1986). It gives the best estimation of plant achieved by following the micro-fermentation method yield, growth and development, and thus the productive described by Sampaio et al. (2007). The fermentation mi- potential of the vine for given conditions (Yuste 1995). cro-deposit consisted of a glass jug (1 gallon) with a cap The limits of shoot weight cited in the literature are 20- for alimentary use perforated in the centre, through which 40 g/shoot. Sauvignon data showed low shoot vigour due passed the fermentation value, which was thermosealed to high crop load. Shiraz shoot weight was within normal with food-grade silicone. values mentioned in the literature.

None of the treatments with yeast derivatives affected the vegetative growth of Shiraz or Sauvignon Blanc – neither – 68 – Impact on Agronomic Parameters in Vines and Wine Quality of Foliar Treatments with Specific Fractions of Yeast Derivatives

Table 1. RD-LM treatment effect on Shiraz and RD-LA treatment 2.2 Vegetative/Productive Balance effect on Sauvignon Blanc re pruning weight (kg/m²), shoot weight (g) and % of shoot humidity. Statistical significance: *, Dry Weight **, ***, ns: significant differences for p0.05, 0.01, 0.001, or not significant, respectively. Knowing that dry weight production indicates a vineyard’s capacity or potential (Carbonneau and Casteran 1986) Shoot % Hum Variety Treatment PW (kg/m2) weight (g) shoot and that dry weight accumulated on renewable parts pro- Control 0.23 30.18 55.9 vides a good approximation of the overall productivity of Shiraz RD-LM 0.25 30.43 55.8 the vine by assuming 88–93% of the dry weight produced Sig. ns ns ns annually (Williams 1996), we can conclude from treat- Shoot % Hum ments that there was no effect on vineyard capacity or Variety Treatment PW (kg/m2) weight (g) shoot potential. Control 0.17 16.80 60.0 Sauvignon Like with vegetative growth, the experimental treatments RD-LA 0.15 15.28 61.9 Blanc had no effect on the humidity conditions of leaves and Sig. ns ns ns bunches, which change during the ripening period. Shoot % Hum Variety Treatment PW (kg/m2) weight (g) shoot Dry Weight Distribution Control 0.23 30.18 55.9 According to the dry weight distribution data obtained Shiraz RD-LM 0.25 30.43 55.8 by various authors (Fregoni 1980, Fernandez et al. 1997, Sig. ns ns ns Williams and Grimes 1987, and Williams and Biscay Shoot % Hum Variety Treatment PW (kg/m2) weight (g) shoot 1991), our trial showed a lower % of dry weight accumu- Control 0.17 16.80 60.0 lated in stems and a higher % in leaves. The % in bunches Sauvignon RD-LA 0.15 15.28 61.9 was similar to that obtained by these authors. This indi- Blanc Sig. ns ns ns cates the low vigour of the shoots, especially in Sauvignon Blanc, due to the high number of shoots per plant and the Control 0.17 16.80 60.0 Sauvignon water stress present. RD-LT 0.14 14.40 63.6 Blanc Sig. ns ns ns Dry weight distribution between leaves, stems and bunch- the vigour estimated by the shoot weight nor the vine’s es did not have a significant effect, and where grape vegetative expression as evidenced by the pruning weight. harvests varied the values were within normal ranges This was to be expected, since the yeast derivatives were (between 54% and 64% of dry weight corresponding to applied after vegetative growth was well underway and in renewable parts). some aspects (such as on the stems) almost complete. (The conditions of the shoots, like humidity content, were not affected during the ripening period.)

Table 2. RD-LM treatment effect on Shiraz and RD-LA treatment effect on Sauvignon Blanc re dry weight and % of humidity in leaves (LDW and %LH) and dry weight and % of humidity in the bunches (BDW and %BH). Statistical significance: *, **, ***, ns: significant differences for p0.05, 0.01, 0.001, or not significant, respectively.

LEAVES BUNCHES LEAVES BUNCHES Variety Treatm. LDW %LH BDW %BH Variety Treatm. LDW %LH BDW %BH Control 55.22 63.6 80.20 70.1 Control 36.04 61.0 47.94 72.1 Sauvignon Shiraz RD-LM 51.14 62.2 68.39 71.2 RD-LA 33.03 61.2 58.71 72.2 Blanc Sig. ns ns ns ns Sig. ns ns ns ns

Table 3. RD-LM treatment effect on dry weight distribution in the renewable parts of Shiraz vines, and RD-LA treatment effect on dry weight distribution in the renewable parts of Sauvignon Blanc vines. Statistical significance: *, **, ***, ns: significant differences for p0.05, 0.01, 0.001, or not significant, respectively. Variety Treatm. % stems % leaves % bunches Variety Treatm. % stems % leaves % bunches Control 12.14 32.03 55.84 Control 11.44 31.31 57.25 Sauvignon Shiraz RD-LM 14.02 31.08 54.90 RD-LA 9.53 26.67 63.80 Blanc Sig. ns ns ns Sig. ns ns ns

– 69 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

Physiology Gas Exchange Leaf Water Potential According to the schema by Medrano et al. (2002) on The leaf water potential measured at noon ( mid) de- vine photosynthetic response to drought with stomatal creased as the cycle progressed, even under conditions conductance used as a reference parameter, we see that of sufficient moisture (Williams and Matthews, 1990), the values at the time of maximum photosynthetic activity remaining relatively stable after veraison (Williams and suggest moderate drought. The stomatal effects are pre- Grimes, 1987). In Table 4 we see that in maturation, the  dominant, and photosynthesis is restored once the leaf is mid decreased with respect to pre-veraison values. rehydrated (Flexas et al., 1999), and no stomatal effects are detectable (Naor et al., 1994, Flexas et al., 2002, and Furthermore, according to Williams and Mathews (1990), Maroco et al ., 2002). For measurements performed at leaf water potential measured at noon must be lower noon, the values show severe water stress with predomi- than -1.3 MPa for premature leaf abscission to occur, and nance of non-stomatal effects and no recovery of photo- Kriedman and Smart (1971) observed that leaf water po- synthesis after the leaf is rehydrated (Dühring 1988). tential measured at 12 p.m. began to limit photosynthesis from -1.2 MPa. According to the values obtained by these Unlike leaf water potential, physiological measurements authors, Shiraz and Sauvignon Blanc vines in our trial ex- at the leaf level in Shiraz were not significantly affected perienced since pre-veraison limiting values for photosyn- either at maximum photosynthesis or at noon by the ap- thesis, and explain the senescence of basal leaves already plication of LM. We consider the significant reduction in present on this period.OK the net assimilation rate at midday with respect to maximum photosynthesis noteworthy, as values at maturation According to Vallone et al. (1997), leaf water potential at are much lower than pre-veraison values, which shows noon in the ripening period has an effect on yield components. that the effects of water status are more limiting at noon and when the ripening period has advanced. The leaf water potential although in some cases showed significant differences only in the LA treatment on Sauvi- 2.4 Yield Components gnon Blanc is worthy of considerationt. For LA treatment, Yield components are already determined at the time the leaf water potential were significantly reduced com- when the yeast derivatives are applied, except berry pared to the control during the ripening period. weight, which tends to double during ripening. As might

Table 4. RD-LM treatment effect on Shiraz and RD-LA treatment effect on Sauvignon Blanc leaf water potential (MPa) at maximum photosynthesis ( max) and at midday ( mid). Statistical significance: *, **, ***, ns: significant differences for p0.05, 0.01, 0.001, or not significant, respectively. Variety Date Treatment Ψmax Ψmid Variety Date Treatment Ψmax Ψmid Control -1.50 -1.44 Control -1.26 -1.35 Pre- Pre- RD-LM -1.33 -1.38 RD-LA -1.22 -1.39 veraison veraison Sig. ** ns Sauvignon Sig. ns ns Shiraz Control -1.60 -1.67 Blanc Control -1.22 -1.58 Maturation RD-LM -1.46 -1.62 Maturation RD-LA -1.64 -1.72 Sig. * ns Sig. ** *

Table 5. RD-LM treatment effect on Shiraz re net photosynthesis rate (μmol CO2/m2 leaves) and stomata conductance (mol H2O/m2 leaves). Statistical significance: *, **, ***, ns: significant differences for p0.05, 0.01, 0.001, or not significant, respectively. Variety Date s.h. Treatm. Photos. Cond. Date s.h. Treatm. Photos. Cond. Control 7.48 0.0876 Control 7.70 0.1948 maximum RD-LM 8.39 0.1002 maximum RD- LM 6.71 0.1638 Sig. ns ns Sig. ns ns Pre- Control 3.11 0.0454 Control 1.57 0.0248 Shiraz Maturation veraison midday RD-LM 3.37 0.0311 midday RD-LM 1.43 0.0206 Sig. ns ns Sig. ns ns s.h. s.h. Sig. ns ns Sig. ns ns *applic. *applic.

– 70 – Impact on Agronomic Parameters in Vines and Wine Quality of Foliar Treatments with Specific Fractions of Yeast Derivatives be expected, yield components were not significantly af- treatments did not have any impact on carbohydrate ac- fected in any of the treatments or varieties. Overall values cumulation during the ripening period. for fertility (number of clusters/shoots), bunch weight and berry weight were quantitatively small, probably due to c. Total Acidity the high number of shoots present in the vineyard and the Evolution of the total titratable acidity (expressed as g/L of very limited water availability. tartaric acid) was characterized by an increase in the herbaceous phase followed by a decrease throughout matu- 2.5 Evolution of Berry Composition during Ripening ration, coinciding with the increase in sugar content and a. Berry Weight increased berry weight (Esteban et al. 1999 and Hrazdina Berry weight is a basic estimator of growth and the qual- et al. 1984). In figure 3 (next page) we see that treatments ity/quantity of the harvest. did not affect the degradation of acids during ripening. Significant differences were found only in the sampling d. pH from August 29, which coincided with the first harvest, showing greater berry weight vs. the control in the case The pH of the must depends on the balance between con- of RD-LA treatment, as we saw earlier in the yield com- centrations of free organic acids and their salts, with po- ponents. tassium as the primary cation (Smart and Coombe, 1983). In figure 4 we see that treatments did not affect this bal- b. Total Soluble Solids (°Brix) ance. During ripening, grapes are a major sink for carbohydrates from the active leaves and reserve structures (Roubelakis- During the ripening period, the technological maturity of Angelakis 2009). We can see in figure 2 (next page) that the pulp did not undergo significant changes in sugar con-

Table 6. RD-LM treatment effect on Shiraz and RD-LA treatment effect on Sauvignon Blanc yield components. Statistical significance: *, **, ***, ns: significant differences for p0.05, 0.01, 0.001, or not significant, respectively.

Bunch Berry Num. Bunch Berry Num. Kg Kg Variety Date Treatm. Weight Weight Bunches Variety Date Treatm. Weight Weight Bunches /vine /vine (g) (g) / Shoot (g) (g) / Shoot 1st Harvest Control 94.21 3.30 0.96 1.39 1st Harvest Control 81.63 3.23 0.78 1.38 09/03/2013 RD-LM 96.37 3.43 0.98 1.38 08/29/2013 RD-LA 83.13 3.92 0.86 1.61 2nd Harvest Control 100.50 3.54 0.98 1.49 2nd Harvest Control 75.39 3.52 0.78 1.41 09/18/2013 RD-LM 94.45 3.37 0.94 1.40 09/10/2013 RD-LA 83.62 3.82 0.82 1.39 3rd Harvest Control 96.30 3.18 0.93 1.35 3rd Harvest Control 67.67 2.91 0.78 1.41 Sauvignon Shiraz 09/24/2013 RD-LM 80.65 2.85 0.85 1.37 Blanc 09/18/2013 RD-LA 72.37 3.21 0.86 1.40 Harvest Sig. ns ns ns ns Harvest Sig. ns ns ns ns Application Sig. ns ns ns ns Application Sig ns ns ns ns Harv. * Harv. * Sig. ns ns ns ns Sig. ns ns ns ns Applic. Applic.

Shiraz berry weight (g) Sauvignon Blanc berry weight (g) 1.2 1.2

1.0 1.0 * 0.8 0.8

0.6 0.6 Control Control 0.4 0.4 RD-LM RD-LA 0.2 0.2

0 0 07/29/2013 08/13/2013 08/28/2013 09/12/2013 07/29/2013 08/13/2013 08/28/2013 09/12/2013

Figure 1. RD-LM treatment effect on Shiraz and RD-LA treatment effect on Sauvignon Blanc berry weight (g) from pre-veraison to the third harvest

– 71 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

Shiraz “Brix” Sauvignon Blanc “Brix” 30 30

25 25

20 20

Control Control 15 15 RD-LM RD-LA 10 10

5 5 07/29/2013 08/13/2013 08/28/2013 09/12/2013 07/29/2013 08/13/2013 08/28/2013 09/12/2013

Figure 2. RD-LM treatment effect on Shiraz and RD-LA treatment effect on Sauvignon Blanc re °Brix from pre-veraison to the third harvest

Shiraz Total Acidity (g TH2/L) Sauvignon Blanc Total Acidity (g TH2/L) 47 47 42 42 37 37 32 32 27 27 Control Control 22 22 RD-LM RD-LA 17 17 12 12 7 7 2 2 07/29/2013 08/13/2013 08/28/2013 09/12/2013 07/29/2013 08/13/2013 08/28/2013 09/12/2013

Figure 3. RD-LM treatment effect on Shiraz, and RD-LA and RD-LT treatment effect on Sauvignon Blanc re total ccidity (g TH2/L) from pre- veraison to the third harvest

Shiraz pH Sauvignon Blanc pH 4.5 4.5

4.0 4.0

3.5 3.5

Control Control 3.0 3.0 RD-LM RD-LA 2.5 2.5

2.0 2.0 07/29/2013 08/13/2013 08/28/2013 09/12/2013 07/29/2013 08/13/2013 08/28/2013 09/12/2013

Figure 4. RD-LM treatment effect on Shiraz and RD-LA treatment effect on Sauvignon blanc re pH from pre-veraison to the third harvest

– 72 – Impact on Agronomic Parameters in Vines and Wine Quality of Foliar Treatments with Specific Fractions of Yeast Derivatives tent, expressed as °Brix, total acidity and pH. The control In figure 6, as expected, the anthocyanin content increas- and yeast derivative treatments had similar values. es during ripening to a maximum at second harvest, then decreases due to “overripening” linked to a phenomenon e. Total Polyphenol Index of degradation and usually an aging phenomenon in the The Index of Total Polyphenols theoretically represents the berry. As a consequence of this cellular aging, a substan- sum of the contribution of phenolic anthocyanins from tial decrease in cohesion between the cells occurs, with the skins, the tannins from the skins and the tannins from degradation of cell walls and membranes. This increases the seeds. (See figure 5) the extractability of anthocyanins. f. Total Anthocyanins and Extractable Anthocyanins g. Tannins

TPI Control RD-LM 80

40 SHIRAZ IPT Harvest x Application *** 20 Harvest * Application ns Total Polyphenols Index Polyphenols Total 0 1st Harvest 2nd Harvest 3rd Harvest

Figure 5. RD-LM treatment effect on Shiraz re Total Polyphenol Index (TPI) from pre-veraison to the third harvest. Statistical significance: *, **, ***, ns: significant differences for p0.05, 0.01, 0.001, or not significant, respectively.

Total Ant. Control RD-LM 3500 3000 2500 2000 SHIRAZ Ant TOTAL 1500 Harvest x Application *** 1000 Harvest * 500 Application ns

Total Anthocyanins (mg/L) Anthocyanins Total 0 1st Harvest 2nd Harvest 3rd Harvest

Extra Ant. Control RD-LM 1500

1000 SHIRAZ Ant EXTRA Harvest x Application *** 500 Harvest *** Application * 0

Extractable (mg/L) Anthocyanins 1st Harvest 2nd Harvest 3rd Harvest

Figure 6. RD-LM treatment effect on Shiraz re total anthocyanins and extractable anthocyanin concentration (mg malvidin/L) at the three harvests. Statistical significance: *, **, ***, ns: significant differences for p0.05, 0.01, 0.001, or not significant, respectively.

– 73 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

Tannins Control RD-LM 6 5 4 3 SHIRAZ Tannins 2 Harvest x Application *** Harvest ns 1 Application ***

Tannins (mg epicatechin/g) Tannins 0 1st Harvest 2nd Harvest 3rd Harvest

Figure 7. RD-LM treatment effect on Shiraz re tannin concentration (mg epicatechin/g) at the three harvests. Statistical significance: *, **, ***, ns: significant differences for p0.05, 0.01, 0.001, or not significant, respectively.

Tannins are synthesized during the first stage of berry creased significantly at all harvest times when yeast de- growth or “herbaceous growth,” and synthesis ends short- rivatives were applied. ly after veraison. We find this significant effect on Shiraz phenolic maturity When skin maturity was studied in Shiraz to ascertain the when LM yeast derivatives are applied of particular note. influence of yeast derivatives (LM) on phenolic maturity, Values were always higher on the last two harvest dates it was found that the effect depended on harvest time and compared to the control, only lower on the first harvest date in the case of total polyphenols. The best and maxi- generally on interaction between harvest time and treat- mum values obtained with yeast derivatives products sug- ment with yeast derivatives. This was the case both for gest that research needs to continue the total polyphenol index and for total and extractable anthocyanins. In the latter case, the treatment regardless 2.6 Vinification of the harvest date was also shown to have a significant All repetitions were fermented at the three harvest times effect. Also noteworthy was that Shiraz tannin content in- in both cultivars and all treatments studied, for a total of

Table 7. Actions and timing of winemaking process on Shiraz and Sauvignon Blanc at the three harvest times for each treatment. In both cases the yeast used for fermentation was EC-1118 (Lallemand Inc.). The enzyme added in Sauvignon Blanc musts was lalzyme Cmax (Lallemand Inc). Action Harvest + Nutrient End of End of Stabilization Variety Harvest Reduless™ End of Vatting + Vit™ Maceration Homogenized + Tasting Addition Fermentation Inoculation Addition Devatting Bottled 10 Feb 1st Harvest 03 Sep 04 Sep 09 Sep 15 Sep 17 Sep 27 Sep 09 May 10 Feb Shiraz 2nd Harvest 18 Sep 19 Sep 25 Sep 03 Oct 03 Oct 14 Oct 09 May 10 Feb 3rd Harvest 24 Sep 25 Sep 03 Oct 16 Oct 18 Oct 05 Nov 09 May

Action Harvest + Clarification Nutrient End of End of Stabilization Variety Harvest Vatting + Reduless™ + Vit™ Fermentation Homogenized + Tasting Enzyme + Addition Inoculation Addition Devatting Bottled Refrigeration 20 Jan 1st Harvest 29 Aug 01 Sep 05 Sep 09 Sep 12 Sep 23 Sep 09 May Sauvignon 20 Jan 2nd Harvest 10 Sep 12 Sep 19 Sep 22 Sep 24 Sep 04 Oct Blanc 09 May 20 Jan 3rd Harvest 18 Sep 20 Sep 25 Sep 03 Oct 08 Oct 18 Oct 09 May

– 74 – Impact on Agronomic Parameters in Vines and Wine Quality of Foliar Treatments with Specific Fractions of Yeast Derivatives

Table 8. RD-LA treatment effect on Sauvignon Blanc and RD-LM treatment effect on Shiraz re triangle taste test. Level of significance 5%, 1% and 0.1% for a panel of 11 tasters (according to Roessler et al. 1948). Variety/ Level of Level of Level of Harvest Harvest Harvest Product signifiance signifiance signifiance

Sauvignon 1st Harvest ns 2nd Harvest 5% 3rd Harvest 1% Blanc 1st Harvest 1% 2nd Harvest 5% 3rd Harvest ns RD-LA 1st Harvest 5% 2nd Harvest 5% 3rd Harvest 5% 1st Harvest 5% 2nd Harvest 1% 3rd Harvest 1% Shiraz 1st Harvest 5% 2nd Harvest 1% 3rd Harvest 1% RD-LM 1st Harvest 1% 2nd Harvest 1% 3rd Harvest 1%

48 microvinifications. The table on page 74 shows the ac- SAUVIGNON BLANC tions and dates relative to the winemaking process for the The particularly interesting sensory analysis of Sauvignon experimental vinifications in both cultivars. Blanc reveals that depending on the time of harvest, the wines are more aromatic and feature a more enjoyable 2.7 Sensory Evaluations mouthfeel when treated with yeast derivatives. In the case Triangle Test of Shiraz, significantly favourable mouthfeel and color The Triangle Taste Test makes it possible to determine with LM treatment always depended on the time of har- differences between two products with similar qualities. vest. Tasters are offered three samples at random, two of which are from the same wine. Three repetitions of each treat- Conclusions ment were tested. Applying LA in Sauvignon Blanc and LM in Shiraz improved the aromatic expression of Sauvignon Blanc wines For a panel of 11 tasters, the level of significance accord- and the phenolic maturity of Shiraz, with higher anthocy- ing to Roessler et al. (1948) for the triangle taste test is anin and tannin content and enhanced sensory impres- 5% if 7 out of 11 answers are correct, 1% if 8 out of 11 sions in mouthfeel. answers are correct and 0.1% if 10 out of 11 answers are correct. Below are the results: Applying yeast derivatives between veraison and the start of ripening (LA and LT in Sauvignon Blanc and LM in Shi- Except in one of the comparisons of the first harvest and in raz) did not affect the functionality of the vine, leaf activ- another of the third harvest, the difference was significant ity, yield components, vegetative growth or technological between Sauvignon Blanc wines from vines treated with maturity of the grapes. RD-LA versus those from untreated vines. These conclusions should be consolidated with results of future trials In the case of Shiraz, the wines from vines treated with RD-LM showed high levels of significance when compared to wines from untreated vines. Acknowledgments We would like to thank Lallemand Inc for its experimental It is worth noting that the differences in many cases ex- and economical support. ceeded 70%, which adds substantial weight to the sensory analysis that revealed a general preference for wines We would also like to make special mention of CEIGRAM from vines treated with yeast derivatives. (Centro de Estudios e Investigación para la Gestión de Riesgos Agrarios y Medioambientales) for its help in proj- Descriptive Test ect management.

A sensory descriptive analysis was performed after it was Special thanks, too, to Grupo de Investigación en Viticul- determined that the wines from vines treated with RD- tura de la UPM for its major contribution to this research. LM and RD-LA were significantly different from the wines We would also like to thank Finca Contancia for its full from untreated vines. cooperation in the use of its facilities. Figures 9 and 10 (next page) present the results of the descriptive analysis. – 75 – NEW OUTLOOK IN VITICULTURE AND THE IMPACT ON WINE QUALITY

Control RD-LA

SB. 1st Harvest AROMA SB. 2nd Harvest AROMA SB. 3rd Harvest AROMA

Intensity Quality Intensity Quality Intensity Quality

SB. 1st Harvest Mouthfeel SB. 2nd Harvest Mouthfeel SB. 3rd Harvest Mouthfeel Intensityl Intensityl Intensityl

Quality Length Quality Length Quality Length

Figure 8. Tasting analysis examining the impact of RD-LA treatment on Sauvignon Blanc wines at the three different harvest times. Statistical significance: *, **, ***, ns: significant differences for p0.05, 0.01, 0.001, or not significant, respectively.

Control RD-LA

Shiraz 1st Harvest Shiraz 2nd Harvest Shiraz 3rd Harvest

Colour Colour Colour

Volume Tannin Volume Tannin Volume Tannin intensity intensity intensity

Tannin Tannin Tannin Astringency Astringency Astringency maturity maturity maturity

Bitterness Bitterness Bitterness

Figure 9. Palette evaluation examining the impact of RD-LM treatment on Shiraz wines at three different harvest times. Statistical significance: *, **, ***, ns: significant differences for p0.05, 0.01, 0.001, or not significant, respectively.

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